electronics application &
installation guide
1 Introduction and Purpose . . . 6
1.1 Applicable Engines . . . 6
1.2 Electronic Applications Contacts . . . 6
1.3 Safety . . . 6
1.3.1 Warning — Welding . . . 7
1.3.2 Warning — Electrostatic Paint Spraying . . . 7
1.3.3 Warning — Jump-Starting . . . 7
2 Engine Component Overview . . . 8
2.1 Electronic Control Unit (ECU) . . . 8
2.2 Sensor Details . . . 8
2.2.1 Intake Manifold Pressure Sensor . . . 8
2.2.2 Intake Manifold Temperature Sensor . . . 9
2.2.3 Coolant Temperature Sensor . . . 9
2.2.4 Fuel Rail Pressure Sensor . . . 9
2.2.5 Fuel Pump Solenoid . . . 10
2.2.6 Electronic Unit Injectors . . . 10
2.2.7 Crankshaft Speed/Timing Sensor . . . 10
2.2.8 Pump/Camshaft Speed/Timing Sensor . . . 11
2.2.9 Oil Pressure Sensor . . . 11
2.2.10 Wastegate Regulator . . . 11
2.3 Engine Component Diagrams and Schematics . . . 12
2.3.1 C6.6 Factory-Installed Wiring and Components . . . 12
2.3.2 C6.6 Engine Wire Harness Schematic . . . 13
2.3.3 C4.4 Factory-Installed Wiring and Components . . . 14
2.3.4 C4.4 Engine Wire Harness Schematic . . . 15
2.3.5 C6.6 Principal Engine Electronic Components . . . 16
2.3.6 C4.4 Principal Engine Electronic Components . . . 17
2.4 Customer System Overview Key Elements . . . 18
2.4.1 Connection, Power, and Grounding . . . 18
2.4.2 Indication Starting and Stopping the Engine . . . 18
2.4.3 Controlling the Engine . . . 18
2.5 Required Components to Install . . . 18
2.6 Optional Customer-Installed Components . . . 19
2.6.1 Typical Customer-Installed Component Diagram . . . 20
2.6.2 Example OEM Schematic . . . 21
2.6.3 Example 1 Basic Engine Application . . . 21
2.6.4 Example 2 Construction Application . . . 21
2.6.5 Example 3 Industrial Open Power Unit Application . . . 21
2.6.6 Example 4 Agricultural Application . . . 21
2.6.7 Example 1 — Basic Schematic OEM Harness . . . 22
2.6.8 Example 2 — Construction Schematic OEM Harness . . . 23
2.6.9 Example 3 — Industrial Open Power Unit Schematic OEM Harness . . . 24
2.6.10 Example 4 — Agricultural Schematic OEM Harness . . . 25
3 Power and Grounding Considerations . . . 26
3.1 Engine Block Grounding . . . 26
3.1.1 Ground Stud on Starter Motor . . . 26
3.1.2 Ground Connection to Tapping on Engine Block . . . 26
3.3 ECU Power Supply Circuit Resistance . . . 28
3.3.1 Battery (+) Connection . . . 30
3.3.2 Battery (-) Connection . . . 30
3.3.3 Correct Method of ECU Battery Connection. . . . 31
3.3.4 Correct Method of ECU Battery Connection. . . . 32
3.4 Engine ECU Power Supply Circuit Resistance Test . . . 33
3.4.1 Test Procedure . . . 34
3.4.2 Inductive Energy — Fly-back Suppression Diode . . . 34
4 Connectors and Wiring Harness Requirements . . . 35
4.1 Requirements . . . 35
4.1.1 ECU Connector . . . 35
4.1.2 Connector Layout . . . 36
4.1.3 Tightening the OEM Connector . . . 36
4.1.4 ECU Connector Wire Gauge Size . . . 36
4.1.5 ECU Connector Terminals . . . 36
4.1.6 Terminal Retention . . . 37
4.1.7 Hand Crimping For Prototype Machines and Low Volume Production . . . 37
4.1.8 ECU Connector Sealing Plug Installation Guidelines . . . 38
4.1.9 OEM Harness Retention at the ECU . . . 38
4.1.10 Machine Crimping For High Volume Production . . . 39
4.2 Harness Wiring Standards . . . 39
4.2.1 General Recommendations for Machine Wiring Harnesses . . . 39
4.2.1.1 Connectors . . . 39
4.2.1.2 Cable Routing. . . . 39
4.2.1.3 Mounting Location for Electronic Modules . . . 40
4.2.1.4 Electromagnetic Compliance (EMC) . . . 40
4.2.1.5 Diagnostic Connector . . . 40
4.2.1.6 Termination Resistor . . . 41
4.2.1.7 Pin Information . . . 41
5 Starting and Stopping the Engine . . . 42
5.1 Starting the Engine . . . 42
5.2 Stopping the Engine (and Preventing Restart) . . . 43
5.2.1 Ignition Keyswitch . . . 43
5.2.2 Emergency Stop Button . . . 43
5.2.3 Battery Isolation Switches . . . 44
5.2.4 Remote Stop Button . . . 44
5.2.5 Datalink Stops . . . 45
5.2.6 Common Problems With the Application of Stop Devices . . . 45
6 Engine Speed Demand . . . 46
6.1 Analogue Sensor . . . 47
6.1.1 Device Description . . . 47
6.1.2 Analogue Sensors — Connection Details . . . 47
6.1.3 Evaluating Component Compatibility . . . 48
6.1.3.1 Analogue Input Test Circuit . . . 48
6.1.3.2 Idle Validation Switch Test Circuit . . . 48
6.1.4 Test Procedure . . . 49
6.1.5 Required Values . . . 50
6.2 PWM Sensor — Compatibility . . . 50
6.2.1 Device Description . . . 50
6.2.2 Component Compatibility . . . 50
6.2.3 Connection Details . . . 51
6.2.4 PWM Throttle — ET Configurable Parameters . . . 51
6.3 PTO Mode . . . 51
6.3.1 PTO Mode On/Off Switch . . . 51
6.3.2 PTO Mode Set/Lower Button . . . 51
6.3.3 PTO Mode Raise/Resume Button . . . 52
6.3.4 PTO Mode Disengage Switch . . . 52
6.3.5 PTO Mode Preset Speed . . . 52
6.3.6 PTO Mode Lamp . . . 52
6.3.7 PTO Mode — ET Configurable Parameters . . . 52
6.3.8 Example of PTO Mode Operation . . . 53
6.4 Multi-Position Throttle Switch (MPTS) . . . 53
6.4.1 Multi-Position Throttle Switch — ET Configurable Parameters . . . 55
6.5 Torque Speed Control TSC1 (Speed Control Over CAN) . . . 55
6.6 Arbitration of Speed Demand . . . 55
6.6.1 Manual Throttle Selection Switch . . . 55
6.7 Ramp Rate . . . 55
6.8 Throttle Calibration . . . 56
6.8.1 Throttle Parameter Description . . . 58
6.8.1.1 Diagnostic Lower Limit . . . 58
6.8.1.2 Lower Position Limit . . . 58
6.8.1.3 Initial Lower Position Limit . . . 58
6.8.1.4 Lower Dead Zone . . . 58
6.8.1.5 Initial Upper Position Limit . . . 58
6.8.1.6 Upper Position Limit . . . 58
6.8.1.7 Upper Dead Zone . . . 58
6.8.1.8 Diagnostic Upper Limit . . . 58
6.8.2 Throttle Calibration Function . . . 59
6.8.2.1 Idle Validation Switch . . . 63
7 Cold Starting Aid . . . 64
7.1 Control of Glow Plugs by the Engine ECU . . . 64
7.1.1 Relay, Fuse, and Cable Gauge Specification . . . 64
7.1.2 Wait-to-Start/Start Aid Active Lamps . . . 65
7.1.3 OEM/Operator Control or Override of the Glow Plugs . . . 66
7.1.4 Ether Cold Start Systems . . . 66
7.1.5 Water Jacket Heaters . . . 67
7.1.6 Ambient Temperature Sensor — ET Configurable Parameter . . . 67
8 Operator Displays . . . 68
8.1 Displays . . . 68
8.1.1 Gauge Drivers . . . 68
8.1.2 Lamp Outputs . . . 68
8.1.3 Indicator Lamps Logic . . . 69
8.1.4 Datalink-Driven Intelligent Displays . . . 70
8.1.5 Minimum Functional Specification for J1939 Display. . . . 70
8.2 Engine Software Features . . . 71
8.2.1 Engine Monitoring System . . . 71
8.2.1.1 General . . . 71
8.2.1.2 Warning . . . 71
8.2.1.3 Derate . . . 71
8.2.1.4 Shutdown . . . 71
8.2.2 Monitoring Mode — ET Configurable Parameters . . . 71
8.2.3 Monitoring Mode Thresholds . . . 72
8.2.3.1 Coolant Temperature . . . 72
8.2.3.2 Engine Oil Pressure . . . 72
8.2.3.3 Intake Manifold Temperature . . . 72
8.2.4 Other Derate Reasons . . . 73
9 Monitored Inputs for Customer-Fitted Sensors . . . 74
9.1 Configurable States . . . 74
9.2 Air Filter Service Indicator — Air Intake Restriction Switch . . . 74
9.3 Coolant Low Level Switch . . . 75
9.4 Fuel in Water Trap Switch . . . 75
10 Engine Governor . . . 76
10.1 Governor . . . 76
10.1.1 All Speed . . . 76
10.1.2 Torque Limit Curve . . . 76
10.1.3 Droop . . . 76
10.1.4 High Speed Governor (Governor Run-Out) . . . 76
10.2 Auxiliary Governor . . . 78
10.3 Rating Selection Via Service Tool . . . 78
10.4 Mode Switches . . . 78
10.4.1 Rating and Droop Changes Requested Via the J1939 Datalink . . . 79
10.4.2 Service Maintenance Indicator . . . 79
11 Using the ET Service Tool. . . . 80
12 Datalink Support . . . 81
12.1 SAE J1939 . . . 81
12.1.1 Summary of Key J1939 Application Issues . . . 81
12.1.2 Physical Layer . . . 81
12.1.3 Network Layer . . . 81
12.1.4 Application Layer . . . 81
13 J1939 Supported Parameters Quick Reference Summary Table . . . 82-85 14 J1939 Parameters — Detailed Descriptions . . . 86
14.1 Sending Messages to the ECU . . . 86
14.2 J1939 Section 71 — Vehicle Application Layer . . . 87-104 14.3 J1939 Section 73 — Diagnostic Layer . . . 105-106 14.4 Supported Parameters — Section 21 — Simplified Descriptions . . . 107
14.5 Supported Parameters — Section 81 Network Management — Detailed Descriptions . . . 107
15 Appendices . . . 108
15.1 Appendix 1 — ECU J1 Connector Terminal Assignments . . . 108-109
1 Introduction and Purpose
This document will provide necessary information for correct electrical and electronic installation of C4.4 or C6.6 Industrial engines into an off-highway machine. Caterpillar expects that there will be some additions and
modifications to this document as the engine program development continues, and as OEM requests for
information not currently addressed are added. The information herein is the property of Caterpillar Inc. and/or its subsidiaries. Without written permission, any copying or transmission to others, and any use except that for which it is loaned is prohibited.
1.1 Applicable Engines
The information contained is the best available at the time of authoring to describe the application and installation requirements of the production software as of January 2007.
Some engines shipped before this date will not have all the features described in this document. Likewise, some additional features will be added after this date. Contact the electronic applications team for the latest
information on software feature release dates.
1.2 Electronic Applications Contacts
If the information in this document is incomplete, incorrect, or further details are required, please contact your applications engineer.
Electronic Applications Team
Mark Tegerdine — Electronic Application Team Leader Telephone: +44(0) 1733 583222
Email: [email protected]
1.3 Safety
Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools in order to perform these functions properly.
The information in this publication was based upon current information at the time of publication. Check for the most current information before you start any job. Caterpillar dealers will have the most current information. Improper operation, maintenance or repair of this product may be dangerous. Improper operation, maintenance or repair of this product may result in injury or death.
Do not operate or perform any maintenance or repair on this product until you have read and understood the operation, maintenance, and repair information.
Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The warnings in this publication and on the product are not all-inclusive. If a tool, a procedure, a work method, or an operating technique that is not specifically recommended by Caterpillar is used, you must be sure that it is safe for you and for other people. You must also be sure that the product will not be damaged. You must also be sure that the product will not be made unsafe by the procedures that are used.
1.3.1 Warning — Welding
Welding can cause damage to the on-engine electronics. The following precautions should be taken before and during welding:
• Turn the engine off. Place the ignition keyswitch in the OFF position.
• Disconnect the negative battery cable from the battery. If the machine is fitted with a battery disconnect switch, open the switch.
• Clamp the ground cable of the welder to the component that will be welded. Place the clamp as close as possible to the weld.
• Protect any wiring harnesses from welding debris and splatter.
DO NOT use electrical components in order to ground the welder. Do not use the ECU or sensors or any other electronic components in order to ground the welder.
1.3.2 Warning — Electrostatic Paint Spraying
The high voltages used in electrostatic paint spraying can cause damage to the engine electronics. The damage can manifest itself through immediate failure of components or by weakening electronic components, causing them to fail at a later date.
The following precautions should be taken when using electrostatic paint spraying techniques on engines: • Connect all 64 pins of the ECU J1 connector directly to the spraying booth ground.
• Connect the engine block to ground at 2 points. Ensure that good screwed connections onto bright metal are used.
1.3.3 Warning — Jump-Starting
Jump-starting an engine can cause higher than normal voltages to appear across the battery terminals. Care must be taken that this does not exceed the recommended maximum voltage for the ECU.
2 Engine Component Overview
2.1 Electronic Control Unit (ECU)
The A4E2 ECU is an electronic control device, fundamentally a computer that governs engine speed and torque output. The ECU processes sensor measurements from the connected sensors to determine fuel quantity, fuel timing, fuel pressure, and intake pressure. The device is assembled to a special mounting plate fitted to the engine. The location is common on both C4.4 and C6.6 engines, left hand side close to the fuel rail. The device has two connection sockets, one for the engine wire harness (J2) that is blue in color and the other for the machine OEM harness connection (J1) that is grey in color. There are two ECU options, a fueled-cooled version and an air-cooled version. The choice of option depends on the maximum ambient temperature (see mechanical installation guide for details of fuel connection requirements and temperature restrictions).
2.2 Sensor Details
2.2.1 Intake Manifold Pressure Sensor
The intake manifold pressure sensor measures the air pressure inside the intake manifold, after the turbo. There are two sensor options dependent on the choice of rating. The operating range of the sensor options differs. The range is either 0-339 kPa absolute or 0-440 kPa absolute.
The sensor is used to determine atmospheric (barometric) pressure. During certain operating conditions the ECU will take a snapshot of the measured pressure to set the atmospheric pressure value. The atmospheric pressure is used to determine the atmospheric related fuel limits (if any); e.g., at high altitude fuel may be limited during cranking to prevent turbo over-speed. The ECU also uses the atmospheric value to calculate gauge pressure of other absolute engine pressure sensors.
When the engine is running, the sensor measurement is used as an input parameter to calculate torque and air fuel ratio limits. This helps prevent black smoke during transient engine conditions, mainly during acceleration or upon sudden load application; i.e., if intake manifold pressure is too low for the requested fuel, the fuel is limited to prevent the over-fuel condition. The measurement will also be used to select certain timing maps.
Intake manifold pressure is also used to control the turbo wastegate regulator, if fitted. The turbo wastegate regulator control system regulates intake manifold pressure to a desired value, calibrated in the software. In order to do this, the software needs to know the actual value of intake manifold pressure, hence the need for the sensor measurement.
If the intake manifold pressure sensor/circuit fails, a low default value is used in the software. The wastegate regulator control (if fitted) will go to open loop, whereby the resultant intake manifold pressure will be low (as determined by the wastegate hardware chosen) and fuel will be limited under certain engine conditions, effectively providing a fuel/torque derate.
2.2.2 Intake Manifold Temperature Sensor
This sensor measures the temperature inside the inlet air manifold. There are two sensor options on the C4.4 engine depending on the turbo arrangement. The operating range of the sensors differs. The range is either -40°C to +120°C or -40°C to +200°C (used on straight turbo options). The C6.6 engine uses the -40°C to +120°C option.
Note: This is the sensor to which the engine is calibrated. Intake air temperature measurement is very
sensitive to location. If the OEM adds additional inlet air temperature monitoring; for example, during prototype evaluation, it should be anticipated that there may be a difference of several degrees Celsius between the engine sensor and the OEM sensor.
Intake manifold temperature measurement is used as an input to the cold start strategy. When the engine is running the sensor measurement is used as an input parameter to calculate torque and air fuel ratio limits. The OEM has no connection to this sensor, but if the intake air is required by some machine system; for example, for fan control strategy, the data can be accessed on the J1939 datalink.
It is possible, if extreme temperatures are measured at the intake, that the engine will derate. In the event of a derate, an event code will be generated on the J1939 datalink or displayed on the service tool, and the warning lamp will illuminate.
2.2.3 Coolant Temperature Sensor
The coolant temperature sensor measurement is used as an input to the cold start strategy. The measurement is also used to select certain maps at 0°C, 50°C, 65°C, and 70°C. The engine is considered warm at 65°C. The fuel delivery characteristics will change dependent on the engine temperature. The sensor is also used for activating the glow plugs for cold engine starting and for detecting high coolant temperatures for raising an event. The range is -40°C to +120°C
If the sensor/circuit fails, a default value is used and a diagnostic code is raised. For glow plug control if this sensor/circuit is faulted, the intake manifold air temperature sensor is used. It is possible that with this sensor/circuit in a failure condition, white smoke may result during a cold engine start. The high coolant temperature event will not be raised under this fault condition.
The sensor reading of coolant temperature is also used to determine the maximum fuel allowed during engine starting. If the sensor/circuit fails, it is possible the engine will not start under cold engine conditions.
It is possible, if the coolant temperature exceeds the design limits, that the engine will derate. In the event of a derate, a fault code will be generated on the J1939 datalink or displayed on the service tool, and the warning lamp will illuminate.
2.2.4 Fuel Rail Pressure Sensor
The fuel rail pressure sensor is used to measure the fuel pressure in the high-pressure fuel rail. (The fuel in the fuel rail feeds all injectors. Injection takes place when each injector is electrically operated.)
The fuel rail pressure measurement is used in conjunction with the high-pressure fuel pump to maintain the desired fuel pressure in the fuel rail. This pressure is determined by engine calibrations to enable the engine to meet emissions and performance objectives.
If the fuel rail pressure sensor/signal is faulted, a diagnostic code is set with a warning; a default value used and a 100 percent engine derate results. The default value for fuel rail pressure will allow the engine to run in a
2.2.5 Fuel Pump Solenoid
The fuel rail pump solenoid is used to control the output from the high-pressure fuel pump. It is energized when fuel is required to be pumped into the high-pressure fuel rail. Varying the energize time of the solenoid controls the fuel delivery from the pump. The earlier the solenoid is energized (degrees before TDC), the more fuel is pumped into the fuel rail.
The solenoid forms part of the fuel rail pressure closed loop control system in conjunction with the fuel rail pressure sensor, ECU, and software. The fuel rail pressure sensor measures the fuel rail pressure; the signal is processed by the ECU, and software and compared to the desired fuel rail pressure for the given engine operating conditions. The control algorithmcontrols the fuel rail pump solenoid energize time. There is no OEM connection to this component.
If the fuel rail pump solenoid fails, it is likely that fuel will not be pumped into the fuel rail and engine shutdown or failed start is expected.
2.2.6 Electronic Unit Injectors
Each fuel injector contains a solenoid to control the quantity of fuel injected. Both positive and negative wires to each solenoid are wired directly back to the ECU.
There is no OEM connection to this component. Voltages of up to 70V are used to drive the injectors. The signals to the injectors are sharp pulses of relatively high current. The OEM should ensure that any systems that are sensitive to electromagnetic radiation are not in proximity to the harness components that lead to the injectors.
2.2.7 Crankshaft Speed/Timing Sensor
The crankshaft speed-timing sensor is a Hall-effect sensor. The sensor works in conjunction with the timing ring fitted to the engine crankshaft.
The sensor produces a signal as the timing ring/crank rotates past the sensor. The ECU uses this signal to calculate crankshaft speed and crankshaft position. The crank speed/timing signal is used during normal engine running since it is more accurate than the signal obtained from the cam speed/timing sensor.
If the crank speed/timing sensor signal is lost or faulted, the engine is capable of starting provided the cam speed/ timing signal is healthy. A diagnostic and warning will be raised if the fault occurs during engine running. A full derate will result since the engine is not guaranteed to be emissions compliant due to the accuracy of the cam speed/timing signal. The diagnostic and derate will not be raised during engine cranking (if fault present), but the service tool will provide a means to read the condition of the cam and crank speed signals to aid fault finding. The OEM has no connection to this sensor. If the OEM
requires accurate engine speed information, it may be obtained from the SAE J1939 datalink. The software includes logic to prevent reverse engine running.
2.2.8 Pump/Camshaft Speed/Timing Sensor
The camshaft speed/timing sensor works in conjunction with the timing ring fitted inside the high pressure fuel pump. The sensor produces a signal as the timing ring/pump rotates past the sensor. The ECU uses this signal to calculate camshaft speed, camshaft position and engine cycle. The cam speed/timing signal is required for determining the correct engine cycle and is also used for limp-home operation in the event of the crank speed sensor/circuit being faulted/lost.
If the camshaft speed/timing sensor/signal is lost or faulted, the engine will not start (since engine cycle is not known from the crank signal only), but if the engine is already running, no engine performance effect will be noticed. A diagnostic and warning will be raised if the fault occurs during engine running. The diagnostic will not be raised during engine cranking, but the service tool will provide a means to read the condition of the cam and crank speed signals to aid fault finding. The software includes logic to compensate for minor timing errors.
2.2.9 Oil Pressure Sensor
The oil pressure sensor measures the engine oil pressure in kPa. Oil pressure is used for engine protection, whereby if insufficient oil pressure is measured for a given speed, an event for low oil pressure would be raised. The low oil pressure threshold is defined as a map against engine speed. Currently, two levels of event are specified. Level 1 is the least severe and raises a warning. Level 3 is the most severe and raises a warning which requests that the engine be shutdown. Automatic engine shutdown can be configured for certain applications, such as gensets, to occur when a level 3 event is raised.
If the oil pressure sensor fails, a diagnostic is raised and a default value is used by the software, which has been chosen to be a healthy (high) pressure value. It is not possible to raise an event while an oil pressure diagnostic is present.
2.2.10 Wastegate Regulator
The regulator controls the pressure in the intake manifold to a value that is determined by the ECU. The wastegate regulator provides the interface between the ECU and the mechanical system that regulates intake manifold pressure to the desired value that is determined by the software.
2.3 Engine Component Diagrams and Schematics
2.3.1 C6.6 Factory-Installed Wiring and Components
Intake Manifold Pressure
Intake Manifold Temperature
Fuel Rail Pressure Wastegate Regulator
(If Equipped)
Electronic Unit Injectors
Coolant Temperature Oil Pressure Pump/Cam Speed/ Timing Crank Speed/Timing Fuel Pump 64 Pin Plug Diagnostic (If Equipped)
A4E2 ECM
J1
2.3.2 C6.6 Engine Wire Harness Schematic
6 INJECTOR CYLINDER 6 RETURN
62 INJECTOR CYLINDER 6
7 INJECTOR CYLINDER 5 RETURN
63 INJECTOR CYLINDER 5
40 FMP SENSOR GROUND
37 TEMPERATURE SENSOR RETURN
10 SPEED SENSOR POWER (+8V)
52 CRANK SPEED/TIME SENS SIG
53 PUMP /CAM SPEED SENS SIG
42 IMT SIGNAL
8 INJECTOR CYLINDER 4 RETURN
64 INJECTOR CYLINDER 4
33 INJECTOR CYLINDER 3 RETURN
59 INJECTOR CYLINDER 3
34 INJECTOR CYLINDER 2 RETURN
58 INJECTOR CYLINDER 2
35 INJECTOR CYLINDER 1 RETURN
57 INJECTOR CYLINDER 1
OIL PRESSURE SENSOR
FUEL MANIFOLD PRESSURE SENSOR COOLANT TEMPERATURE SENSOR INTAKE MANIFOLD TEMPERATURE SENSOR CRANKSHAFT SPEED/ TIMING SENSOR
PUMP / CAM SPEED SENSOR FUEL PUMP SOLENOID A B D E F G DIAGNOSTIC CONNECTOR (9 PIN) 1 2 1 2 1 2 1 2 1 2 2 1 3 24 J1939 + 23 J1939 -20 CDL-21 CDL+
45 BAT - (FOR COMMS ADAPTER)
18 BAT+ (FOR COMMS ADAPTER)
51 FMP SENSOR SIGNAL
48 FMP SENSOR POWER SUPPLY (+5V)
43 COOLANT TEMP SIGNAL
56 OIL PRESSURE SENSOR SIGNAL
39 OIL PRESSURE SENSOR RETURN
47 OIL PRESSURE SENSOR PWR (+5V)
55 IMP SIGNAL
38 IMP RETURN
46 IMP POWER SUPPLY (+5V)
1 2 3 4 1 2 3 4 1 2 3 4 2 1 3 2 1 3 1 2 ELECTRONIC WASTEGATE ACTUATOR
25 FUEL PUMP SOLENOID PWM SIG
26 FUEL PUMP SOLENOID RETURN
19 WASTEGATE RETURN 17 WASTEGATE PWM SIGNAL A4E2 ECU J2 Connector INJECTOR CYLINDER 6 INJECTOR CYLINDER 5 INJECTOR CYLINDER 4 INJECTOR CYLINDER 3 INJECTOR CYLINDER 2 INJECTOR CYLINDER 1 T957 BK T951 BK T952 BK T958 BK T953 BK T959 BK T954 BK T960 BK T955 BK T961 BK T956 BK T962 BK X931YL X925PK X930 GY X924 BR X929BU X923 OR X928 GN X922 WH X927 YL X921 PK X926 GY X920 BR 101 RD 229 BK 944 OR 945 BR Y793 YL Y792 PK C211 BK M795 WH Y951 PU Y950 YL L731 BR C967 BU 995 BU R997 OR Y948 BR Y946 BU L730 OR Y947 BR 994 GY T997 OR T993 BR X731 BU 996 GN E965 BU P920 BR INTERNAL (ROCKER COVER) EXTERNAL C H J INTAKE MANIFOLD PRESSURE SENSOR
NOT ALWAYS FITTED ON FIXED SPEED
2.3.3 C4.4 Factory-Installed Wiring and Components
Intake Manifold Pressure
Intake Manifold Temperature
Fuel Rail Pressure Wastegate Regulator
(If Equipped)
Electronic Unit Injectors
Coolant Temperature Oil Pressure Pump/Cam Speed/ Timing Crank Speed/Timing Fuel Pump 64 Pin Plug Diagnostic (If Equipped)
A4E2 ECM
J1
2.3.4 C4.4 Engine Wire Harness Schematic
34 INJECTOR CYLINDER 4 RETURN
58 INJECTOR CYLINDER 4
8 INJECTOR CYLINDER 3 RETURN
64 INJECTOR CYLINDER 3
40 FMP SENSOR GROUND
37 TEMPERATURE SENSOR RETURN
10 SPEED SENSOR POWER (8V)
52 CRANK SPEED/TIME SENS SIG
53 PUMP /CAM SPEED SENS SIG
42 IMT SIGNAL
7 INJECTOR CYLINDER 2 RETURN
63 INJECTOR CYLINDER 2
35 INJECTOR CYLINDER 1 RETURN
57 INJECTOR CYLINDER 1
OIL PRESSURE SENSOR
FUEL MANIFOLD PRESSURE SENSOR COOLANT TEMPERATURE SENSOR INTAKE MANIFOLD TEMPERATURE SENSOR CRANKSHAFT SPEED/ TIMING SENSOR
PUMP / CAM SPEED SENSOR FUEL PUMP SOLENOID A B D E F G DIAGNOSTIC CONNECTOR (9 PIN) 1 2 1 2 1 2 1 2 1 2 2 1 3 24 J1939 + 23 J1939 -20 CDL-21 CDL+
45 BAT - (FOR COMMS ADAPTER)
18 BAT+ (FOR COMMS ADAPTER)
51 FMP SENSOR SIGNAL
48 FMP SENSOR POWER SUPPLY (5V)
43 COOLANT TEMP SIGNAL
56 OIL PRESSURE SENSOR SIGNAL
39 OIL PRESSURE SENSOR RETURN
47 OIL PRESSURE SENSOR PWR (5V)
55 IMP SIGNAL
38 IMP RETURN
46 IMP POWER SUPPLY (5V)
1 2 3 4 1 2 3 4 2 1 3 2 1 3 1 2 ELECTRONIC WASTEGATE ACTUATOR
25 FUEL PUMP SOLENOID PWM SIG
26 FUEL PUMP SOLENOID RETURN
19 WASTEGATE RETURN 17 WASTEGATE PWM SIGNAL A4E2 ECU J2 Connector INJECTOR CYLINDER 3 INJECTOR CYLINDER 2 INJECTOR CYLINDER 1 T957 BK T951 BK T952 BK T958 BK T953 BK T959 BK T954 BK T960 BK X929BU X923 OR X928 GN X922 WH X927 YL X921 PK X926 GY X920 BR 101 RD 229 BK 944 OR 945 BR Y793 YL Y792 PK C211 BK M795 WH Y951 PU Y950 YL L731 BR C967 BU 995 BU R997 OR Y948 BR Y946 BU L730 OR Y947 BR 994 GY T997 OR T993 BR X731 BU 996 GN E965 BU P920 BR INTERNAL (ROCKER COVER) EXTERNAL C H J INTAKE MANIFOLD PRESSURE SENSOR
NOT ALWAYS FITTED ON FIXED SPEED
ENGINES INJECTOR CYLINDER 4
2.3.5 C6.6 Principal Engine Electronic Components Crank Speed Sensor Coolant Sensor Oil Pressure Sensor Intake Temperature Pump/Cam Speed Sensor Fuel Rail Pressure Sensor Intake Pressure Sensor ECU Fuel Pump
Solenoid Note: Variable
Wastegate Fitted to Right Hand Side
2.3.6 C4.4 Principal Engine Electronic Components Fuel Pump Solenoid Fuel Rail Pressure Sensor ECU J1 Connector Crank Speed Sensor Oil Pressure Sensor Pump/Cam Speed Sensor Intake Manifold Pressure Sensor Coolant Temperature Sensor Intake Temperature Sensor Note: Wastegate Regulator Fitted to Right Hand Side of
2.4 Customer System Overview Key Elements
The engine can be wired and configured many different ways dependent on the requirements of the OEM. The key elements to consider are:
2.4.1 Connection, Power, and Grounding
The engine ECU requires electrical power. The requirements for powering the ECU need careful review. It is important to understand how to connect the ECU to the machine battery; more detail is given in the power and grounding section of this document.
2.4.2 Indication Starting and Stopping the Engine
With the battery connected, a single connection to the ECU is required to initialize the ECU. Once initialized the ECU will be ready to control the engine. It is important to consider how the power to pin 40 is controlled; most machines use a simple keyswitch to start and stop the engine. There are specific recommendations for stopping the engine that are specified in the starting and stopping section of this guide. Mandatory requirements regarding operator indication are in place; see the operator display section of this document.
2.4.3 Controlling the Engine
There are specific requirements in this document for controlling engine speed and auxiliary components. Further information is available in the speed demand section of this document.
2.5 Required Components to Install
Mandatory or Required Components Section
Battery Power and Grounding Considerations
Circuit Protection Power and Grounding Considerations
Keyswitch Starting the Engine
Warning Lamp Operator Displays
Shutdown Operator Displays
Wait-to-Start Lamp Operator Displays
Glow Plug Relay Cold Starting Aid
2.6 Optional Customer-Installed Components*
Optional Components Section
Low Oil Pressure Lamp Operator Displays
PTO Mode Lamp Operator Displays
Maintenance Due Lamp Operator Displays
Remote Shutdown Switch (Normally Open) Stopping the Engine
Coolant Level Sensor Monitored Inputs for Customer Fitted Sensors
Water Fuel Sensor Monitored Inputs for Customer Fitted Sensors
Air Filter Restriction Switch Monitored Inputs for Customer Fitted Sensors
PWM Throttle Position Sensor Engine Speed Demand
Analogue Throttle Position Sensor with
Idle Validation Switch (1) Engine Speed Demand
Analogue Throttle Position Sensor with
Idle Validation Switch (2) Engine Speed Demand
Throttle Selection Switch Engine Speed Demand
Multi-Position Switch Engine Speed Demand
PTO On/Off Switch Engine Speed Demand
PTO Set/Lower Switch Engine Speed Demand
PTO Raise/Resume Switch Engine Speed Demand
PTO Disengage Switch Engine Speed Demand
Mode Switch (1) Engine Governor
Mode Switch (2) Engine Governor
Maintenance Due Reset Switch Additional Options
Ambient Temperature Sensor Additional Options
2.6.1 Typical Customer-Installed Component Diagram Circuit Protection (Mandatory) Keyswitch PWM Throttle Analogue Throttle with IVS Warning Lamp Stop Lamp
Air Filter Restriction Switch
Wait to Start Lamp Low Oil Pressure Lamp
Service Tool Connector
Coolant Level Switch
J1939 Termination Resistor Maintenance Due Lamp
PTO Raise/Resume Button PTO Set/Lower Button PTO On/Off Switch
PTO Disengage Modes Switch 1 Modes Switch 2 Shutdown Switch Glow Plug Relay Maintenance Due Reset Switch Magnetic Switch
+
-Battery Battery Isolation Switch IVS
2.6.2 Example OEM Schematic
The engine can be configured and wired many different ways dependent on the requirements of the OEM. The following four example schematics and descriptions provide a guide for the OEM.
2.6.3 Example 1 Basic Engine Application
This solution is suitable for applications where very little integration or additional engineering is a requirement when compared to the solution used for a mechanical engine. This solution can be used in most mechanically governed engine replacement situations. The OEM needs to consider only basic functions: power supply, operator indication, cold start aid, and a simple method of controlling the engine speed.
2.6.4 Example 2 Construction Application
An application where the engine, in response to an arrangement of switched inputs will operate at one of a range of defined speeds. This is suitable for applications where the device has multiple operating speeds that are defined for the specific output reasons, for simplicity of operator use, or for operation dependent upon the environment — e.g., quiet modes. This could include auxiliary engine on-road sweeper, multiple speed water pumps, etc. There are sixteen possible set speeds based on four discrete ECU inputs. In addition to the keyswitch, a separate engine shutdown switch is used to stop the engine.
2.6.5 Example 3 Industrial Open Power Unit Application
An application where the engine, in response to a control input such as a button press, accelerates from idle speed up to the pre-defined operating engine speed. Once at the pre-defined operating speed, the engine speed may be raised or lowered by increment/decrement button presses. This is suitable for enhancing some of the applications of the single speed (set speed) control or to provide a variable speed control without having a throttle pedal/lever. This functionality may benefit when the user wants to use “set speed operation,” but with the capability to adjust it themselves — users may have a favorite operating speed. This could include concrete pumps and hydraulic driven machines.
2.6.6 Example 4 Agricultural Application
The application will allow single or twin throttles, engine twin set speed control, multi mode operation, integrated display drive, etc. This set-up is suitable for applications where the customer requires a high degree of operator control over the machine’s behavior. It is one of the most complex applications. Typically, this is used in mobile applications that may be driven to the place of work and require operator selectable speed operation while performing their chosen task. This could include tractors, combines, and backhoe loaders.
2.6.7 Example 1 — Basic Schematic OEM Harness A4E2 ECU J1 CONNECTOR OFF ON START IGNITION KEY
SWITCH STOP LAMP
WARNING LAMP
7 BATTERY + NOTE 7
1. N/A
2. Fuse value depends on Mag Switch circuit current 3. N/A
4. Fit suppression diodes across relay coils 5. Glow Plug fuse rating differs between 4cyl and 6cyl engines and system voltage
6. Starter motor control circuits will vary 7. Fuse value dependant on system voltage
NOTES
UNCONTROLLED DOCUMENT FOR INDICATION ONLY Caterpillar Confidential Green
Battery
Chris Crawford 21st AUG 2006 Basic OEM Wiring Schematic
PWM THROTTLE SENSOR 8 BATTERY + 15 BATTERY + 16 BATTERY + 1 BATTERY -2 BATTERY -3 BATTERY -9 BATTERY -10 BATTERY -60 STOP LAMP 59 WARNING LAMP
57 START AID CONTROL 40 IGNITION KEYSWTICH 5A
63 COLD START LAMP COLD START - WAIT TO START LAMP
LOW OIL PRESSURE LAMP
62 LOW OIL PRESSURE LAMP (OPTIONAL)
43 SENSOR SUPPLY 8V 53 PWM THROTTLE SENSOR INPUT TO GLOW PLUGS GLOW PLUG RELAY 33 SENSOR RETURN TO STARTER MOTOR MAG SWITCH J1 PLUG NOTE 5 NOTE 4 NOTE 2
2.6.8 Example 2 — Construction Schematic OEM Harness A4E2 ECU J1 CONNECTOR OFF ON START IGNITION KEY
SWITCH STOP LAMP
WARNING LAMP
7 BATTERY + NOTE 7
1. CAN shield connection at ECM is optional 2. Fuse value depends on Mag Switch circuit current 3. CDL connection may be used for secondary diagnostic connection
4. Fit suppression diodes across relay coils NOTES
UNCONTROLLED DOCUMENT FOR INDICATION ONLY Caterpillar Confidential Green
Battery
Chris Crawford 21st AUG 2006 Construction OEM Wiring Schematic
8 BATTERY + 15 BATTERY + 16 BATTERY + 1 BATTERY -2 BATTERY -3 BATTERY -9 BATTERY -10 BATTERY -60 STOP LAMP 59 WARNING LAMP
57 START AID CONTROL 40 IGNITION KEYSWTICH 5A
50 THROTTLE POSITION SWITCH 2 51 THROTTLE POSITION SWITCH 3 52 THROTTLE POSITION SWITCH 4 10 POSITION ROTARY SWITCH CAN J1939 BUS 120 OHM 20 CAN J1939 + 21 CAN J1939 -22 CAN J1939 SHIELD NOTE 1
63 COLD START LAMP COLD START - WAIT TO START LAMP
LOW OIL PRESSURE LAMP
62 LOW OIL PRESSURE LAMP (OPTIONAL) 23 CDL + 24 CDL -NOTE 3
49 THROTTLE POSITION SWITCH 1
48 SHUTDOWN SWITCH (CLOSE TO STOP) 35 SWITCH RETURN TO GLOW PLUGS GLOW PLUG RELAY TO STARTER MOTOR MAG SWITCH S1 S2 S3 S4 CMN J1 PLUG 120 OHM NOTE 5 NOTE 4 NOTE 2
2.6.9 Example 3 — Industrial Open Power Unit Schematic OEM Harness A4E2 ECU J1 CONNECTOR OFF ON START IGNITION KEY
SWITCH STOP LAMP
WARNING LAMP
7 BATTERY + NOTE 7
SET / LOWER
1. N/A
2. Fuse value depends on Mag Switch circuit current 3. N/A
4. Fit suppression diodes across relay coils 5. Glow Plug fuse rating differs between 4cyl and 6cyl engines and system voltage
6. Starter motor control circuits will vary 7. Fuse value dependent on system voltage
NOTES
UNCONTROLLED DOCUMENT FOR INDICATION ONLY Caterpillar Confidential Green
Battery
PTO MODE LAMP Chris Crawford 21st AUG 2006
IOPU OEM Wiring Schematic
8 BATTERY + 15 BATTERY + 16 BATTERY + 1 BATTERY -2 BATTERY -3 BATTERY -9 BATTERY -10 BATTERY -60 STOP LAMP 59 WARNING LAMP 61 PTO MODE LAMP (OPTIONAL)
57 START AID CONTROL 40 IGNITION KEYSWTICH
RAISE / RESUME ON / OFF
49 PTO MODE - DISENGAGE (NC) 5A
DISENGAGE SWITCH
63 COLD START LAMP COLD START - WAIT TO START LAMP
LOW OIL PRESSURE LAMP
62 LOW OIL PRESSURE LAMP (OPTIONAL) 35 SWITCH RETURN TO GLOW PLUGS GLOW PLUG RELAY
50 PTO MODE - RAISE /RESUME 51 PTO MODE - SET/ LOWER 52 PTO MODE - ON / OFF TO STARTER MOTOR MAG SWITCH J1 PLUG NOTE 5 NOTE 4 NOTE 2
2.6.10 Example 4 — Agricultural Schematic OEM Harness A4E2 ECU J1 CONNECTOR OFF ON START IGNITION KEY
SWITCH STOP LAMP
WARNING LAMP
7 BATTERY + NOTE 7
SET / LOWER
1. CAN shield connection at ECM is optional 2. Fuse value depends on Mag Switch circuit current 3. CDL connection may be used for secondary diagnostic connection
4. Fit suppression diodes across relay coils NOTES
UNCONTROLLED DOCUMENT FOR INDICATION ONLY Caterpillar Confidential Green
Battery
PTO MODE LAMP Chris Crawford 21st AUG 2006
Agricultural OEM Wiring Schematic
8 BATTERY + 15 BATTERY + 16 BATTERY + 1 BATTERY -2 BATTERY -3 BATTERY -9 BATTERY -10 BATTERY -60 STOP LAMP 59 WARNING LAMP 61 PTO MODE LAMP (OPTIONAL)
57 START AID CONTROL 40 IGNITION KEYSWTICH
33 SENSOR RETURN 54 ANALOGUE THROTTLE INPUT 1
55 ANALOGUE THROTTLE INPUT 2 45 IDLE VALIDATION (IVS 1) N/C
44 IDLE VALIDATION (IVS 2) N/C
RAISE / RESUME ON / OFF
49 PTO MODE - DISENGAGE (NC) 5A 41 SENSOR SUPPPLY 5V ANALOGUE THROTTLE SENSOR 1 ANALOGUE THROTTLE SENSOR 2 DISENGAGE SWITCH MODE SWITCH 1 MODE SWITCH 2 39 MODE SWITCH 1 46 MODE SWITCH 2 CAN J1939 BUS 120 OHM 20 CAN J1939 + 21 CAN J1939 -22 CAN J1939 SHIELD NOTE 1
63 COLD START LAMP COLD START - WAIT TO START LAMP
LOW OIL PRESSURE LAMP
62 LOW OIL PRESSURE LAMP(OPTIONAL) 23 CDL + 24 CDL -NOTE 3
47 THROTTLE SELECTION SWITCH
35 SWITCH RETURN TO GLOW
PLUGS GLOW PLUG
RELAY
50 PTO MODE - RAISE /RESUME 51 PTO MODE - SET/ LOWER 52 PTO MODE - ON / OFF 42 SENSOR SUPPPLY 5V 34 SENSOR RETURN TO STARTER MOTOR
MAG SWITCH
THROTTLE SELECTION SWITCH
J1 PLUG 120 OHM
MAINTENANCE DUE LAMP
58 MAINTENANCE DUE LAMP (OPTIONAL)
36 MAINTENANCE DUE RESETSWITCH MAINTENANCE DUE RESET
SWITCH
NOTE 5
NOTE 4 NOTE 2
3 Power and Grounding Considerations
3.1 Engine Block Grounding
Although the engine electronics are all directly grounded via the ECU connector, it is also necessary that the engine block be properly grounded to provide a good return path for components such as starter motor, alternator, and cold start aids.
Improper grounding results in unreliable electrical circuit paths. Stray electrical currents can damage mechanical components and make electronic systems prone to interference. These problems are often very difficult to
diagnose and repair.
3.1.1 Ground Stud on Starter Motor
If the starter motor has a grounding stud it should be used. The ground connection should preferably be made directly back to the battery negative terminal.
The starter motor ground path must not include any flanges or joints. Painted surfaces and flexible mounts in particular must be avoided. Star washers must not be relied upon to make contact though paint.
The ground cable should be of cross section 67.4 mm2(00 AWG) or greater.
3.1.2 Ground Connection to Tapping on Engine Block
A separate engine block ground should be used in addition to the starter motor ground. A ground cable, direct from the battery negative or starter ground terminal, should be connected to a ring terminal which connects to one of the three tappings shown in diagrams 1 and 2. The tapped holes will be reserved for customer use and can be used for grounding purposes.
If a tapping is used it should be checked to be free of lacquer, paint, and dirt before the connection is made. An M10 metric screw plated with zinc should be used. A washer should retain the ring terminal and the screw tightened to 44 Nm (32 Ib-ft).
Diagram 1 Ground Points 1 & 2
Ground Point
Option 1 Ground Point
3.2 Voltage and Current Requirements
The ECU power supply requirements must be carefully considered when designing the supply circuit; there are specific limitations that must be considered in the design to ensure a reliable consistent power supply to the engine electronic components. The table provides the electrical characteristics and limitations for the A4:E2 ECU.
Voltage Supply System 12V 24V
Max Peak Current 60A 60A
Peak Current Cranking 36A 36A
Max RMS Current* 13A 7.5A
Suggested Fuse Rating** 25A 20A
Sleep Current <8mA <10mA
Min Running Voltage 9V 18V
Max Running Voltage*** 16V 32V
Minimum ECU Voltage During Cranking 5.5V 5.5V
Maximum Total ECU Power Circuit Wire Resistance 50 mOhms 100 mOhms
Target Circuit Resistance 40 mOhms 80 mOhms
*Max RMS current measurements conducted on engine running at rated speed and load. RMS current will vary with engine speed (assuming constant voltage) no lamp drivers or application side components fitted during measurement.
**Suggested fuse ratings are based on automotive blade type fuses and are for guidance only.
***The ECU can survive higher voltages. ECU will survive for at least 2 minutes on a supply voltage of 30V for 12V systems and 48V for 24V systems.
3.3 ECU Power Supply Circuit Resistance
Often during engine cranking the battery voltage will drop to values much lower than the normal system operating voltage. The minimum permissible voltage measured at the ECU during cranking is 6V. The power requirements to drive the engine electronic components such as the injectors and fuel pump circuit remain the same during cranking; for this reason the ECU power supply circuit resistance becomes very important and will affect the voltage seen at the ECU. The table below illustrates the difference between the voltage at the ECU during cranking and normal running conditions:
Parameter Engine Cranking Engine Running
System Voltage at the Battery 8V 13.8V
Engine ECU Current Draw 36A 36A
Total ECU Power Supply Resistance 40 mOhms 40 mOhms
Voltage Drop (I*R) 1.44V 1.44V
The maximum permissible circuit resistance including positive and negative wires is 50mOhms for 12V systems and 100mOhms for 24V systems; however, Caterpillar recommends that this value should not be targeted during design, as it is often difficult to predict the final circuit resistance when considering other factors such as fuse holders, connector resistance and aging. A target calculated circuit resistance including wire and connections of 40mOhms for 12V systems and 80mOhms for 24V systems is recommended. The table below provides typical wire resistance for various cross sections of copper wire.
Wire Gauge Typical Wire Resistance (mOhms) and Length (m) @ 20° C
AWG mm2 2m 4m 6m 8m 10m 6 13.5 2.8 5.6 8.4 11.2 14 8 9 4 8 12 16 20 10 4.5 8 16 24 32 40 12 3 14 28 42 56 70 14 2 20 40 60 80 100
As with all electrical circuits wire should be selected so that the rated maximum conductor temperature is not exceeded for any combination of electrical loading, ambient temperature, and heating effects of bundles, protective braid, conduit, and other enclosures. Consult wire manufacturers’ data sheets for further information.
A4E2 ECU
-+
Battery N e g a ti v e W ir e R e s is ta n c e (O h m s ) P o s it iv e W ir e R e s is ta n c e (O h m s )Circuit Load (ECU) Total Circuit Length
3.3.1 Battery (+) Connection
The ECU requires four un-switched battery positive inputs; the inputs should be permanently connected to the machine battery. When the ignition keyswitch is off, the ECU is in a sleep mode where it draws a very small residual current through the four battery connections. When the ignition keyswitch is turned on the ECU will become active. It is recommended, therefore that the ignition keyswitch is turned to the off position when
connecting or disconnecting the ECU J1 connector, to prevent large sparks which may cause damage to the pins. The power supply to the ECU should be taken from the battery, not from the starter motor terminals, to avoid unnecessary system noise and voltage drops. Note that there are four ECU pins allocated for battery positive. All four pins must be used.
The correct system voltage must be applied (12V or 24V), as the following components on the engine are system voltage sensitive: • Wastegate Regulator • Glow Plugs • Alternator • Starter Motor 3.3.2 Battery (-) Connection
The ECU requires five un-switched battery negative inputs; the inputs should be permanently connected to the machine battery.
Battery Connection — Do Not supply power to the ECU from the starter motor connections:
Starter Motor
Battery Battery
Note: Circuit protection not shown
-+
-+
Wrong
Right
3.3.3 Correct Method of ECU Battery Connection
Correct Power Supply Wiring
• ECU positive wires connected direct to battery, not via starter motor
• Power supply wires go to all four positive pins and all five negative pins on the ECU connector • Negative is wired to the battery rather than return through chassis
• The engine is grounded
Right
Starter Motor ECU Connector Chassis Engine Fuse3.3.4 Incorrect Method of ECU Battery Connection
Incorrect Wiring
• Positive wired via starter motor. High volt drop to ECU on starting.
• Single pin on ECU used for each of positive and negative supply. Possibly exceeding pin ratings and possibly causing risk of arcing or overheating.
• ECU return through chassis — risk of conducted noise and also additional voltage drop. • Engine not grounded — risk of engine component damage.
Starter Motor ECU Connector Chassis Engine Chassis
Wrong
3.4 Engine ECU Power Supply Circuit Resistance Test
It is not possible to accurately measure the machine ECU power supply wire resistance using a standard ohmmeter alone; it is therefore necessary to use a specific test circuit. The diagram and table below detail the test apparatus used in the circuit to determine the engine ECU circuit resistance. The circuit consists of two voltmeters and a resistor connected to the J1 ECU plug that can be switched in and out of circuit using a relay. It is very important to keep the test circuit resistance to a minimum; use a relay with low contact resistance (preferably silver oxide or gold) and short lengths of heavy gauge wire.
Component Caterpillar Part Number Supplier Part Number Quantity
J1 Receptacle 245-1040 12244365 1
2.2 Ohm Resistor 200w N/A N/A 1
Relay (low contact resistance) N/A N/A 1
Pushbutton N/A N/A 1
Voltmeter N/A N/A 2
R1
V1
2.2 Ohms 200 watts Voltmeter 1
7 8 15 16 1 2 3 9 10 J1 Engine ECU Plug
Machine Harness
-+
V2
Voltmeter 2 Machine Battery3.4.1 Test Procedure
Record the measured resistance value of the test resistor used. Disconnect the J1 engine ECU plug from the ECU and connect the test apparatus detailed in the above diagram to the plug. Press the button for three seconds and at the same time record the voltage measured from Voltmeter 1 and Voltmeter 2.
Formula:
Power Supply Circuit Resistance (mOhms) = 1000 * (R1 * (V2 – V1)/V1) V1 = Voltmeter 1 Measured Value
V2 = Voltmeter 2 Measured Value R1 = Measured Resistor Value
Worked Example: V1 = 11.8 V2 = 12 R1 = 2.21 Ohms 1000 * (2.21 * (12 – 11.8)/11.8) 1000 * (2.21 * 0.1695) 1000 * (0.375)
Harness Resistance = 37.5 mOhms
3.4.2 Inductive Energy — Fly-back Suppression Diode
When an inductive load is suddenly switched off, fly-back energy is introduced to the circuit. This can be observed as a voltage spike. When using an ECU output to drive an inductive load such as a relay or solenoid, circuit protection needs to be considered. To prevent unnecessary ECU circuit loading, use relays or solenoids with integral fly-back suppression components to suppress induced fly-back energy.
Relay with Suppression Diode
-4 Connectors and Wiring Harness Requirements
4.1 Requirements
4.1.1 ECU Connector
The A4E2 engine ECU has an integral rectangular 64-pin Delphi Packard socket; the socket is grey in appearance and is the customer/OEM connection point. To make a connection to the engine ECU the components listed in the table below are required.
Qty Description (photo ref.) Delphi Part Number Caterpillar Part Number
1 Plug Assembly (1) 15488667 245-1042
1 Wire Dress Cover (2) 15488664 245-1045
2 Terminal Lock (TPA) (3) 15404650 245-1044
N/A Contact Socket (Terminal) (4) 15359002 245-1047
N/A Sealing Plug (5) 12129557 245-1048
Components required for A4E2 engine ECU connection
4.1.2 Connector Layout
The diagram below illustrates the pin layout, looking from the rear of the connector.
4.1.3 Tightening the OEM Connector
A central 7 mm AF hex screw retains the connector. This screw should be tightened to a torque of 5 Nm+/- 1 (3.7+/-0.7 lb-ft).
Caterpillar does not recommend the use of “non conductive grease” with the ECU connector.
4.1.4 ECU Connector Wire Gauge Size
All connections must be made with 0.82 mm2(18AWG) wire with GXL type insulation.
Min outside diameter (Inc Insulation) = 1.85 mm Max outside diameter (Inc Insulation) = 2.5 mm
4.1.5 ECU Connector Terminals
4.1.6 Terminal Retention
Two terminal position assurance components should be used once all terminals have been crimped and inserted into the connector body. Terminal Position Assurance — Caterpillar part no. 245-1044 (Delphi p/n 15404650).
Note: It is critical that two terminal position assurance components are used.
Connector body and terminal assurance components
When a terminal has been properly crimped and retained, it will be able to withstand a “pull test” of 45N (10 lb).
4.1.7 Hand Crimping For Prototype Machines and Low Volume Production
A hand crimp tool and appropriate die are required for crimping contact sockets — (Delphi p/n 15359002). The hand crimp tool and removal tool for removing the sockets from the connector body are available from Power and Signal Group (PSG).
Caterpillar Hand Crimping Solution
Component Caterpillar Part Number Supplier Part Number
Contact Socket 267-9572 10-613370-020
Crimp Tool Number 1U5804 Deutsch HDT-48-00
Removal Tool 266-1683 15314902
Delphi Solution
Component Caterpillar Part Number Supplier Part Number
Contact Sockets 245-1047 15359002
HT Micro 100W Crimp Tool with Die —
European Use Only N/A HT42000480-1
Delphi Crimp Tool N/A 12129557
4.1.8 ECU Connector Sealing Plug Installation Guidelines
All unused connector socket slots must be filled with sealing plugs — Delphi p/n 12129557.
Due to the small size of the sealing plugs, it may be quicker to install sealing plugs in all cavities and remove those which are not required, rather than to try to fit the sealing plugs when wires have already been inserted into the back of the connector.
Note: Do not use “non-conductive” grease to seal unused terminal cavities. 4.1.9 OEM Harness Retention at the ECU
A wire strain relief component should be used to prevent ECU connector damage. The wire strain relief component is assembled to the engine ECU during engine manufacture and will be supplied on the engine. Wire bundle size may vary between applications. Cable tie/wire tie slots are provided for correct bundle retention. Use the correct slots.
Use strain relief and correct slots for the harness bundle size:
Component Caterpillar Part Number Supplier Part Number
Strain Relief 260-3718 N/A
Small Bundle Medium Bundle Large Bundle
4.1.10 Machine Crimping For High Volume Production
The hand tool may not be the appropriate solution for crimping terminals in a high volume production environment. The OEM’s harness manufacturer should contact PSG directly for details of high volume crimp solutions.
4.2 Harness Wiring Standards
4.2.1 General Recommendations for Machine Wiring Harnesses
The following are general “good practice” for wire harnesses. It is the responsibility of the machine designer to follow standards appropriate to the application type and to the geographical territory where the machine will be operated. These recommendations do not replace in any way any industrial standards or legislative requirements.
4.2.1.1 Connectors
It is strongly recommended that high quality, sealed connectors are used throughout. Automotive standard components are not necessarily suitable as they are often only designed for a very low number of
disconnect/reconnect cycles.
Connectors should be horizontally mounted rather than vertically mounted to prevent ingress of water/chemicals. Whenever possible, connectors should be mounted such that they are protected from direct exposure to extreme cold. Connectors can be damaged by frost if water does penetrate the seals.
Cables should not bend close to the connector seals, as the seal quality can be compromised. The correct wire seal must be selected for the diameter of wire used.
Cables should be selected of an appropriate cross section for the current and voltage drop requirements. Where large numbers of wires go to the same connector, it is essential that no single wire is significantly shorter than the others, such that it is placed under exceptional strain.
4.2.1.2 Cable Routing
Cables should be routed such that bend radii are not too tight. A cable should not be either in compression or tension, nor should it be excessively long or loose, such that sections may become caught or trapped. Clips should be used at regular intervals to support cables. These clips should be of the correct diameter to grip the cable firmly without crushing it.
Ideally, harnesses should not rub against any mechanical components. The only points of contact should be clamps and connectors. If this is not possible, as a minimum they should not touch components that are hot, that move or vibrate, or that have sharp edges.
Conductors carrying high currents or voltages, particularly when these are alternating or switched, should be physically separated from conductors carrying small signal currents. In particular, high current and signal wires should not run parallel in the same harness bundle for any significant distance. Ideally, if high current wires must be in proximity to signal wires, they should cross at right angles.
The engine wire harness should not be used by the installer as a support for any components that are not supplied as part of the engine. For example, external hoses and wires should not be tied to the engine harness.
4.2.1.3 Mounting Location for Electronic Modules
The least harsh possible location should be selected for an electronic component or module, even one that is robustly designed. Select the mounting location carefully, therefore, considering exposure to frost, vibration, heat, mechanical damage, or ingress of water, dust or chemicals.
Care should be taken during design to ensure that components are accessible for repair and possible replacement in the field. Poor maintenance access may lead to poor quality repairs in the field.
4.2.1.4 Electromagnetic Compliance (EMC)
Special measures should be taken to shield cables if the application is to be used in extreme electromagnetic environments — e.g. aluminum smelting plants. If screened cable is used, the screens should be connected to ground at one point only. That point should be central if possible.
4.2.1.5 Diagnostic Connector
A nine-pin diagnostic connector is fitted to the engine wire harness on all industrial engines. Various diagnostic and development tools may use the connector to access the engine data links.
If the connector is inaccessible when the engine is in the application or no connector is fitted to the engine wire harness, provisions should be made to allocate an alternative location for diagnostic connection. In this case it is recommended that a diagnostic connector be wired in a location that can be easily accessed, free from possible water/dirt ingress and impact damage. The engine wire harness must not be changed or modified. To wire a diagnostic connection use the data link pins available on the OEM J1 ECU connector.
It is recommended that all customer-installed nine-pin diagnostic connectors be wired according to the diagram below.
A
B
D
E
F
G
J1939 +
J1939 +
J1939
J1939
-CDL +
CDL
-CDL +
CDL
-21
20
24
23
Battery +
Battery
-Service Tool
Connector
J1
ECU
Mandatory Requirement for Prototype Machines
It is mandatory for all prototype machines to have access to the engine’s CDL/PDL and J1939 CAN data links.
4.2.1.6 Termination Resistor
It is recommended that termination resistors be wired to the OEM machine harness as stated in the SAE standard. If the engine is the only CAN J1939 device ever present on the machine it is not necessary to wire the resistors. It is important to note, however, that if devices such as handheld code readers, CAN PC tools, or navigation systems are installed in the field later, resistors will be required.
Nine-Pin Diagnostic Connector Part Numbers
Description Deutsch Part Number Caterpillar Part Number
Receptacle (with flange) HD10-9-96P 9W-1951
Receptacle HD14-9-96P 8T-8736
Receptacle End Cap HDC-16-9 8C-6354
4.2.1.7 Pin Information
Pin Description Diagnostic Connector J1 OEM 64-Way Connector
Battery + Pin A Battery - Pin B PDL/CDL + Pin D 23 PDL/CDL - Pin E 24 J1939 - Pin F 21 J1939 + Pin G 20
5 Starting and Stopping the Engine
5.1 Starting the Engine
Unlike mechanically controlled fuel systems no customer connection to the fuel pump solenoid is necessary. To activate the engine ECU, battery voltage needs to be constantly applied to pin 40. When the ECU is active the engine crankshaft needs to be rotated above a minimum cranking speed; a typical cranking speed is 180 rpm (this will differ dependent on the application). Once the ECU has determined engine cranking speed and engine position, fuel pressure and delivery will be controlled.
The most popular way to control engine starting is by a specifically designed three-position keyswitch. The keyswitch controls battery voltage to the keyswitch input and the starter motor circuit. Some applications may require a four-position switch to run auxiliary equipment when the engine is not running.
Caterpillar Switch Assembly: 110-7887
Automatic Starting — Some applications need to be started automatically. There is no automatic start feature available on this product. If an automatic start sequence is required the following points must be considered:
• Start Aid — Wait-to-Start Control • Starter Cranking Duration
• Starter Abutment Detection • Number of Start Attempts • Starter Disengagement Speed • Warm-Up Period
• Cool-Down Period
The ECU software considers the engine running when the engine speed is 100 rpm below the desired engine speed or has reached 1400 rpm. At this point, after a predetermined period of time, the engine will switch from cranking fuel maps to running fuel maps. It is important to note that starter motors must be disengaged earlier to prevent the starter motor being driven by the engine. The engine is considered stalled when the engine has dropped below 300 rpm.
When the engine is running, the engine firing order is:
Engine Firing Order
C4.4 1-3-4-2 C6.6 1-5-3-6-2-4 OFF ON START IGNITION KEY SWITCH START 4 3 1 2 POSITION POSITION 1 - OFF POSITION 2 - RUN POSITION 3 - START TERMINALS 2 & 4 1 & 4 1, 3 & 4
5.2 Stopping the Engine (and Preventing Restart)
There is often some confusion about the different methods and devices used to either stop the engine or to prevent it from starting. These devices may be divided into the following categories:
• Ignition Keyswitch • Emergency Stop Button • Battery Isolation Switch • Remote Stop Button • Datalink Stop
Each of these devices is described below to assist the OEM in selecting the method that is most suitable for his machine and his market. It remains, however, the responsibility of the OEM to ensure compliance of the machine with legislation in the territories into which it is sold.
It is recommended that the OEM performs a risk assessment such as a Failure Mode Effects Analysis (FMEA) on the application to determine the most appropriate method of stopping the engine and/or preventing it from being restarted.
5.2.1 Ignition Keyswitch
It is a Caterpillar requirement that all machines have an simple intuitive and accessible method of stopping the engine. This will normally be a directly wired ignition keyswitch. When the keyswitch is turned to the off position or when the key is removed, power must be removed from the ignition keyswitch pin (pin 40) of the ECU J1 connector.
5.2.2 Emergency Stop Button
An emergency stop button is a fail-safe method for an operator to stop a machine to protect people or equipment. Emergency stop buttons are defined by national or international standards in terms of color, functionality, shape, size, latching/locking. In the EU for example, they are described in the Machinery Directive.
For mobile machines, however, true emergency stop buttons are not always appropriate and are rarely fitted, due to the following issues:
• Legislation is designed principally for static industrial machinery (e.g. lathe) where the main power source is mains electricity.
• Stopping a diesel engine in a mobile machine may not always be safe. In particular the vehicle may need the power to move to a safe position (for example off the public highway, or off a railway track).
• In practice it is difficult to find components such as safety relays which are suitable for mounting on mobile machines due to the high vibration and water ingress protection, and the low voltages that occur during starting.
• Fail-safe wiring can be a cause of machine unreliability and can create faults that are difficult to detect in the field.
If a true emergency stop button is required for an application it is recommended that it is implemented such that both the +battery and the ignition keyswitch lines are cut directly by the emergency stop button.
5.2.3 Battery Isolation Switches
Battery isolation switches are usually fitted in the battery or the engine compartment of a machine. On some machines there may be a small number of low current devices which are not switched off by this device; e.g., clocks or anti-theft tracking devices.
The function of a battery isolation switch is as follows:
• Prevent battery discharge during vehicle shipping or storage
• Protect service technicians from danger caused by inadvertent engine crank or start. To offer good protection of service personnel is it possible to provide a switch which can be locked in the open position (e.g., with a padlock) and the key removed and given to the service engineer who is working on the dangerous components.
The battery isolation switch is not a suitable method for stopping an engine, as it is not guaranteed to stop the engine because the ECU may continue to operate with power generated by the alternator.
It is also possible that opening the battery isolation switch when the engine is running will cause an “alternator load dump.” This is a kind of electrical transient that can cause damage to electronic components.
Battery isolation switches are normally fitted in the negative path, close to the battery.
5.2.4 Remote Stop Button
Remote stop is intended to provide a convenient method of stopping the engine. It is not designed to be fail safe and so should not be used to assure the protection of either personnel or equipment.
Remote stop buttons may be used on large machines, which can be operated from ground level and where the operator wants to stop the machine without climbing into the cab.
There are a number of variations on remote stop button circuits. The engine uses a single normally open contact, which must be closed to stop the engine.
The remote stop button will function as follows:
• A single switch to ground input on pin 48 of the ECU J1 connector (several stop buttons can therefore be connected in parallel)
• When the switch is closed (or if a button is pressed for longer than 150mS), the engine will stop. • The ECU will remain on, so it will continue to communicate over J1939 and with the service tool. Note
however that it will continue to draw power from the battery, so if it is left in this state it will eventually result in a flat battery.
• The engine may be restarted by opening the switch and activating the starter motor.
• The red “mushroom” emergency stop buttons must not be used for remote stop functions as they may be mistaken for emergency stop buttons as described above.
35 SENSOR RTN
48 REMOTE STOP SWITCH
ECU J1
