NOTES None.
The Bosch 5.3 ABS computer with tachometer supplies the vehicle speed signal to all areas where this information is needed (instrument panel, engine management,etc...).
This vehicle speed signal will replace the one supplied by the speed sensor located on the gearbox.
The ABS computer calculates the vehicle speed from the speed of the wheels and the circumference of the tyres fitted on the vehicle.
The tyre circumference must be programmed into the memory of a new computer. This consists of entering an index X using the diagnostic tool with the WHEEL DIAMETER CONFIGURATION command.
Value of index X:
Once the index has been entered using the WHEEL DIAMETER CONFIGURATION command, clear the computer memory and then switch off the ignition.
Use the Tachometric index parameter to check that the index has been entered correctly.
AFTER REPAIR Clear the computer memory.
Check again using the diagnostic tool.
FAULT FINDING - CONFORMITY CHECK
NOTES Only check the conformity after a full check using the diagnostic tool.
Order Function Parameter/status checked or
action Display/notes Fault finding
Ensure that the index entered corresponds to the tyres fitted to the vehicle (refer to the
Help section)
None
4
Operation of ABS and brake warning lights 3 seconds when the ignition is switched on
None
5 Detection of brake
pedal positions ET013 BRAKE PEDAL
Ensure that the system recognises the DEPRESSED and RELEASED positions
MR337 Fault finding
FAULT FINDING - HELP USE OF COMMANDS
Control of the solenoid valves for checking the hydraulic system: G03* to G06*
Lift the vehicle in order to be able to turn the wheels and check that they turn freely. Keep the brake pedal depressed to prevent the wheel to be tested from being turned by hand (do not brake so firmly that full brake power is reached).
Enter G0X* Ten cycles of unlocking/locking must be noted for the wheel concerned.
Control of the pump motor: G08*
Tap G08* and press the brake pedal Motor operation for 2 seconds should be detected.
Pump motor and solenoid valve control: G20*
Tap G20* and press the brake pedal Brief motor and solenoid valve operation must be noted.
Bleeding of hydraulic circuits: G15*3* front left/G15*4* front right/G15*5* rear left/G15*6* rear right Apply the procedure described in the section on Bleeding the circuits in the Workshop Repair Manual.
SPECIAL NOTES
REPLACING THE COMPUTER WITH TACHOMETRIC FUNCTION
The Bosch 5.3 ABS computer with tachometer supplies the vehicle speed signal to all areas where this information is needed (instrument panel, engine management,etc...).
This vehicle speed signal will replace the one supplied by the speed sensor located on the gearbox.
The ABS computer calculates the vehicle speed from the speed of the wheels and the circumference of the tyres fitted on the vehicle.
The tyre circumference must be programmed into the memory of a new computer. This consists of entering an index X using the diagnostic tool with the WHEEL DIAMETER CONFIGURATION command.
Value of index X:
Once the index has been entered using the WHEEL DIAMETER CONFIGURATION command, clear the computer memory and then switch off the ignition.
Use the Tachometric index parameter to check that the index has been entered correctly.
FAULT FINDING - CUSTOMER COMPLAINTS
NOTES Only consult this customer complaint after a complete check using the diagnostic tool.
WARNING LIGHT FAULTS
The ABS warning light does not light up for 3 seconds after the ignition is switched on
CHART 1
The ABS warning light is permanently lit with the ignition on (with no fault being indicated by the diagnostic tool)
CHART 2
The ABS warning light and/or brake warning light comes on again after
the engine is started CHART 3
The ABS warning light and/or brake warning light is lit temporarily when driving
CHART 3
The brake warning light does not light up for 3 seconds after ignition is switched on
CHART 4
Brake warning light permanently lit, ignition on CHART 5 The ABS and brake warning lights are lit up with the ignition on CHART 6
FAULTS WHICH OCCUR WHEN BRAKING WITH ABS REGULATION
Locking of one or more wheels CHART 7
Pulling CHART 8
Drift CHART 9
Unexpected ABS operation at low speed and with light pedal pressure CHART 10 Unexpected ABS operation on a poor road surface CHART 11 Unexpected ABS operation with use of special equipment (car phone,
CB, etc...) CHART 12
Lengthening of the brake pedal travel following ABS operation (with
pedal receding when entering ABS regulation) CHART 13
Spongy pedal CHART 14
Brake pedal vibration CHART 15
Noise from the pump, the pipes or the hydraulic unit CHART 16
FAULT FINDING - CUSTOMER COMPLAINTS
NOTES Only consult this customer complaint after a complete check using the diagnostic tool.
OTHER CASES
The ABS and brake warning lights do not light up, with the computer disconnected
CHART 17
No dialogue with the ABS computer CHART 18
FAULT FINDING - FAULT FINDING CHARTS
CHART 1
ABS WARNING LIGHT DOES NOT LIGHT UP FOR 3 SECONDS WHEN IGNITION IS SWITCHED ON
NOTES Only consult this customer complaint after a complete check using the diagnostic tool.
The ABS and brake warning lights light up by the loss of earth on the connections.
Check the 15A fuse for the instrument panel on the passenger compartment fuse board (if the problem is common to all the instrument panel functions).
Switch off the ignition.
Disconnect the computer, then switch on the ignition again.
Does the ABS warning light come on?
no
Check the condition of the ABS warning light bulb and its supply.Check the insulation against earth of the connection between track 20 of the computer
connector and the ABS warning light.
If the fault persists, check the operation of the instrument panel.
yes
Check the computer connections.
Replace the computer if the fault persists.
AFTER REPAIR Perform a road test followed by a test using the diagnostic tool.
FAULT FINDING - FAULT FINDING CHARTS
CHART 2
THE ABS WARNING LIGHT IS PERMANENTLY LIT WITH THE IGNITION ON (with no fault being indicated by the diagnostic tool)
NOTES Only consult this customer complaint after a complete check using the diagnostic tool.
The ABS and brake warning lights light up by the loss of earth on the connections.
Disconnect the R255 front end of engine/ABS connection. Connect track 10 on the instrument panel side to earth and then switch on the ignition.
Has the ABS warning light gone out?
no
Ensure continuity of the connection between the instrument panel and track 10 of the R255.
Check the wiring of the instrument panel connector.
If the fault persists, check the operation of the instrument panel.
yes
Test the connections on the computer connector and the R255.
Ensure continuity of the connection between track 20 of the ABS computer connector and R255 on
track 10.
AFTER REPAIR Perform a road test followed by a test using the diagnostic tool.
FAULT FINDING - FAULT FINDING CHARTS
CHART 3