Page 35 of 57
38C-35
AFTER REPAIRClear the computer memory using command RZ001 Fault memory.
Carry out a road test followed by another check with the diagnostic tool.
V1 MR-376-X76-38C000$120.mif
ANTI-LOCK BRAKING SYSTEM
Fault finding – Interpretation of statuses38C
ABS BOSCH 8.1
Vdiag No.: 18
ET017
CONTINUED 2
Depressed STATUS: Brake pedal released.
– Check the condition and fitting of the brake light switch and fuse F16 of the brake lights.
– Remove and test the operation of the brake light switch:
Continuity between the following
connections:Insulation between the following
connections:
Switch
depressed(Brake
pedal released)5A and AP10 65A and AP10
Switch released (Brake
pedal depressed)65A and AP10 5A and AP10
If the connection or connections are faulty and if there is a repair procedure (see Technical Note 6015A,
Electrical wiring repair, Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check and ensure the insulation to +12 V of connection 65A between the connector of the brake light switch,
component code 160 and the connector of the ABS computer, component code 118.
If the fault is still present, contact the techline.
Page 38 of 57
38C-38V1 MR-376-X76-38C000$140.mif
ANTI-LOCK BRAKING SYSTEM
Fault finding – Command summary table38C
ABS BOSCH 8.1
Vdiag No.: 18
Tool
commandDiagnostic tool title Comments
SC001Check target teethThis command tests the condition of the teeth on each wheel.
Select the command SC001 and follow the instructions.
The test result should be equal to 48 or 44 teeth depending on
the version.
SC006Bleed the hydraulic unit and
brake circuits.This command must be used only in the event of abnormal
lengthening of brake pedal travel during a road test with ABS
regulation (the vehicle must have already been bled using the
conventional procedure).
Select command SC006 and follow the instructions given by the
diagnostic tool.
Page 39 of 57
38C-39
AFTER REPAIRClear the computer memory using command RZ001 Fault memory.
Carry out a road test followed by another check with the diagnostic tool.
V1 MR-376-X76-38C000$150.mif
38C
ABS BOSCH 8.1
Vdiag No.: 18
AC003
AC004
AC005
AC006FRONT LEFT-HAND WHEEL SOLENOID VALVESFRONT RIGHT-HAND WHEEL SOLENOID VALVES
REAR LEFT-HAND WHEEL SOLENOID VALVES
REAR RIGHT-HAND WHEEL SOLENOID VALVES
NOTESConditions of use of the command:
Ignition on, engine stopped and vehicle speed zero.
Before running the commands, check that the battery is properly charged (see 80A,
Battery, Battery: Customer complaints).
These commands test the solenoid valves on each wheel.
Controlling the wheel solenoid valves to check the hydraulic system
Lift the vehicle in order to be able to check that the wheels turn freely. Keep the brake pedal depressed to prevent
the wheel being tested from being turned by hand (do not brake so firmly that full braking power is reached).
Select and confirm the command of the wheel being examined (e.g. Front left-hand wheel solenoid valves, etc.).
Turn the wheel concerned by hand; you should see it go through the locking/unlocking cycles.
ABS8.1X76_V18_AC003/ABS8.1X76_V18_AC004/ABS8.1X76_V18_AC005/ABS8.1X76_V18_AC006
ANTI-LOCK BRAKING SYSTEM
Fault finding – Interpretation of commands
Page 43 of 57
38C-43
AFTER REPAIRClear the computer memory using command RZ001 Fault memory.
Carry out a road test followed by another check with the diagnostic tool.
V1 MR-376-X76-38C000$150.mif
ANTI-LOCK BRAKING SYSTEM
Fault finding – Interpretation of commands38C
ABS BOSCH 8.1
Vdiag No.: 18
SC006BLEEDING THE HYDRAULIC UNIT AND BRAKE CIRCUITS
NOTESConditions of use of the command:
Ignition on, engine stopped and vehicle speed zero.
Before running the command, check that the battery is properly charged (see 80A,
Battery, Battery: Customer complaints).
This command must be used only in the event of abnormal lengthening of brake pedal travel during a road test with
ABS regulation (the vehicle must have already been bled using the conventional procedure).
Select command SC006 and follow the instructions given by the diagnostic tool.
ABS8.1X76_V18_SC006
Page 44 of 57
38C-44V1 MR-376-X76-38C000$160.mif
38C
ABS BOSCH 8.1
Vdiag No.: 18
NOTESOnly consult these customer complaints after a complete check with the diagnostic
tool.
FAULTS DETECTED WHEN BRAKING WITH ABS CONTROL
Locking of one or more wheels ALP2
Pull ALP3
Drift ALP4
Unexpected ABS operation at low speed and with slight pedal pressure ALP5
Unexpected ABS system intervention on a poor road surface ALP6
Unexpected ABS operation when using special equipment (car phone, CB.) ALP7
Extension of brake pedal travel following a regulation phase (with an irregular
pedal when entering regulation).ALP8
Spongy pedal ALP9
Brake pedal vibration ALP10
Noise from the pump, pipes or hydraulic unit ALP11
OTHER CASES
No dialogue with the ABS computer ALP1
ANTI-LOCK BRAKING SYSTEM
Fault finding – Customer complaints
Page 47 of 57
38C-47
AFTER REPAIRClear the computer memory using command RZ001 Fault memory.
Carry out a road test followed by another check with the diagnostic tool.
V1 MR-376-X76-38C000$170.mif
ANTI-LOCK BRAKING SYSTEM
Fault finding – Fault Finding Chart38C
ABS BOSCH 8.1
Vdiag No.: 18
ALP2 Locking of one or more wheels
NOTESOnly address this customer complaint after a complete check with the diagnostic
tool.
Reminder:
Locking of the wheels on a vehicle fitted with ABS or squealing of tyres, interpreted by the customer as locking,
could be related to a normal reaction of the system and should not automatically be assumed to be a fault (braking
with ABS regulation on a very bad road causes considerable squealing).
However, if the wheel(s) is/are actually locking, lift the vehicle so that you can turn the wheels and check for:
– Possible inversion when connecting the speed sensors.
Use parameters PR001 Front right-hand wheel speed, PR002 Front left-hand wheel speed, PR003 Rear
right-hand wheel speed and PR004 Rear left-hand wheel speed by turning the relevant wheels and checking
the consistency of the results obtained.
If the value measured is zero, rotate the other wheels to confirm an electrical inversion of the sensors and repair
the wiring harness.
– Possible inversion of pipes on the hydraulic unit.
Use commands AC003 Front left-hand wheel solenoid valves, AC004 Front right-hand wheel solenoid
valves, AC005 Rear left-hand wheel solenoid valves and AC006 Rear right-hand wheel solenoid valves
while depressing the brake pedal and check for the occurrence of locking/unlocking cycles on the wheel
concerned (see Command summary table). If the cycles do not occur on the wheel tested (wheel remains
locked), check whether they occur on another wheel to confirm reversed pipes.
If the cycles do not occur on one wheel and the pipes have not been inverted, contact the Techline.
ABS8.1X76_V18_ALP2
Page 49 of 57
38C-49
AFTER REPAIRClear the computer memory using command RZ001 Fault memory.
Carry out a road test followed by another check with the diagnostic tool.
V1 MR-376-X76-38C000$170.mif
ANTI-LOCK BRAKING SYSTEM
Fault finding – Fault Finding Chart38C
ABS BOSCH 8.1
Vdiag No.: 18
ALP3 Pull
NOTESOnly address this customer complaint after a complete check with the diagnostic
tool.
Disconnect one wheel speed sensor.
Start the engine and ensure that only the ABS fault warning light comes on. Do not drive the vehicle if the brake
fault warning light is also illuminated because the "braking compensator" function is no longer guaranteed.
Carry out a road test with the ABS thus out of order.
Is the fault still present under these conditions?
Raise the vehicle so that you can rotate the wheels and check:
– whether the speed sensors have been incorrectly
connected,
– whether the pipes on the hydraulic unit have been inverted.
For these two tests, consult and apply the procedures defined
in ALP2 Locking of one or several wheels.
Check the condition and conformity of the ABS targets.
If the fault is still present, contact the techline.If the brake pedal travel is relatively long,
bleed the brake circuit.
If the travel is normal, check the tyre
pressures, the front axle, or for any leaks in
the circuit.
NOYES
ABS8.1X76_V18_ALP3
Page 50 of 57
38C-50
AFTER REPAIRClear the computer memory using command RZ001 Fault memory.
Carry out a road test followed by another check with the diagnostic tool.
V1 MR-376-X76-38C000$170.mif
ANTI-LOCK BRAKING SYSTEM
Fault finding – Fault Finding Chart38C
ABS BOSCH 8.1
Vdiag No.: 18
ALP4 Drift
NOTESOnly address this customer complaint after a complete check with the diagnostic
tool.
Disconnect one wheel speed sensor.
Start the engine and ensure that only the ABS fault warning light comes on. Do not drive the vehicle if the brake
fault warning light is also illuminated because the "braking compensator" function is no longer guaranteed.
Carry out a road test with the ABS thus out of order.
Is the fault still present under these conditions?
Normal behaviour linked to the system operation during
the regulation phase, mainly on surfaces with uneven
grip or which are poorly laid.Road holding fault not related to the ABS.
Check the condition of the brake linings and that
they are to specification and check the tyre
pressures, the front axle, etc.
NOYES
ABS8.1X76_V18_ALP4
