Y1 Y2 Y3
This diagnostic procedure should be used if communication between the Diagnostic Scan Tool
(DST) and the Engine Control Unit (ECU) cannot be established.
SERVICE ADVISOR is a trademark of Deere & Company
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Observable Diagnostics and Tests
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D1 - ECU Does Not Communicate with DST or SERVICE ADVISOR
SERVICE ADVISOR is a trademark of Deere & Company
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D1 - ECU Does Not Communicate With DST or SERVICE ADVISORDiagnostic Procedure
SERVICE ADVISOR is a trademark of Deere & Company
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1 Connection Check IMPORTANT: Do not force probes into connector terminals or damage will result.
Use JT07328 Connector Adapter Test Kit to make measurements in connectors.
This will ensure that terminal damage does not occur.
NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
Perform a preliminary inspection of the ECU connectors, the diagnostic connector, CAN terminator connector, and any connectors between them looking for dirty, damaged, or poorly positioned terminals.
No faulty connection(s):
2 Intermittent Fault Test NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Connect the DST or SERVICE ADVISOR. For instructions on connecting to the DST or SERVICE ADVISOR, see CONNECTING TO DIAGNOSTIC SCAN TOOL (DST) OR SERVICE ADVISOR in Group 160 later in this manual.
2. Make sure all communication cables are properly connected
3. Ignition ON, engine OFF
4. Start the ECU communication software
Can not communicate with ECU:
GO TO 3
Communicates with ECU:
Problem is intermittent. If no other codes are present, see
INTERMITTENT FAULT DIAGNOSTICS earlier in this Group.
SERVICE ADVISOR is a trademark of Deere & Company
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3 Sensor Voltage Test NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition OFF
2. Disconnect any one of the following:
• Fuel temperature sensor
• MAT sensor
• ECT sensor
For sensor location, see ELECTRONIC CONTROL SYSTEM OVERVIEW in Section 03, Group 140 of this manual.
3. Ignition ON
4. Using a multimeter, measure the voltage between both terminals of the selected sensor harness connector.
4.5 volts or above:
GO TO 5
Below 4.5 volts:
GO TO 4
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4 Power Supply Test NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition OFF
2. Disconnect both 30-way ECU connectors.
3. Ignition ON
4. Using a multimeter, measure the voltage between a good chassis ground and terminal E3 in the harness end of the ECU connector.
10.0 volts or above:
Faulty ECU power wiring OR
Faulty ECU.
Below 10.0 volts:
Faulty ECU power fuse OR
Faulty key-on power fuse.
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5 PDM Power Light Test
NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition ON
2. Note power light on the Parallel Data Module (PDM).
Power light is Green:
GO TO 8
Power light is OFF:
GO TO 6
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6 Open in Diagnostic Connector Ground Wire Test
NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition OFF
2. Disconnect the diagnostic cable from the diagnostic connector on main harness.
3. Using a multimeter, measure the voltage between the ground terminal and the power terminal (terminals A and B) in the diagnostic connector on the main harness.
Observable Diagnostics and Tests
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7 Harness Power and Ground Wire Test
NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition OFF
2. Disconnect the diagnostic cable from the diagnostic connector on the main harness.
3. Probe terminal A in the diagnostic connector with test light connected to battery voltage.
Light ON:
Faulty diagnostic connector OR
Open or short to ground in diagnostic connector
8 Open in Harness Circuit Test
NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition OFF
2. Disconnect both 30-way ECU connectors and diagnostic cable from the diagnostic connector
3. Using a multimeter, measure resistance on the harness end of both connectors between:
• Terminal D in the diagnostic connector and terminal L2 in the ECU connector.
• Terminal C in the diagnostic connector and terminal L1 in the ECU connector.
All measurements 5
Open in harness circuit OR
NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition OFF
2. ECU and diagnostic connectors still disconnected.
3. Using a multimeter, measure resistance between terminals C and D in the harness end of the diagnostic connector.
Between 45 - 75 ohms:
GO TO 9
Less than 45 ohms or greater than 75 ohms:
Faulty or missing CAN terminator connector(s).
OR
Open or short in CAN wiring harness
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10 CAN High and Low Voltage Test
NOTE: For wiring information, see D1 - ECU DOES NOT COMMUNICATE WITH DST OR SERVICE ADVISOR supporting information.
1. Ignition OFF
2. Reconnect both 30-way ECU connectors.
3. Ignition ON
4. Using a multimeter, measure voltage between a good chassis ground and:
• Terminal C in the diagnostic connector.
• Terminal D in the diagnostic connector.
Both measurements between 1.5 - 3.5 volts:
Faulty ECU/Cab Harness connection
OR
Faulty diagnostic cable OR
Faulty diagnostic connector OR
Faulty Parallel Port Data Module (PDM)
OR
Faulty diagnostic software/computer configuration OR Faulty ECU
Either measurement less than 1.5 volts or greater than 3.5 volts:
CAN wiring shorted to ground or voltage OR
Faulty ECU
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Observable Diagnostics and Tests
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