Page 50 of 64

ANTI-LOCK BRAKING SYSTEM
Fault finding - Customer complaints
38C
38C - 50V2 MR-372-J84-38C000$858_eng.mif
BOSCH ABS 8.0
Vdiag No.: 0C, 0D, 0E, 0FANTI-LOCK BRAKING SYSTEM
Fault finding - Customer complaints
NOTESOnly consult this customer complaint after a complete check with the diagnostic
tool.
FAULTS DETECTED ON BRAKING WITH ABS/BRAKING REGULATION
LOCKING OF ONE OR MORE WHEELS ALP2
PULLINGALP3
DRIFTALP4
UNEXPECTED ABS OPERATION AT LOW SPEEDS AND SLIGHT PEDAL
PRESSUREALP5
UNEXPECTED ABS OPERATION ON A POOR ROAD SURFACE ALP6
UNEXPECTED ABS OPERATION WHEN USING SPECIAL EQUIPMENT (RADIO
TELEPHONE, CB, etc.)ALP7
LENGTHENING OF BRAKE PEDAL TRAVEL FOLLOWING A REGULATION
PHASE (WITH PEDAL RECEDING WHEN ENTERING THE REGULATION
PHASE)ALP8
SPONGY PEDAL ALP9
BRAKE PEDAL VIBRATION ALP10
NOISES FROM THE PUMP, PIPES OR HYDRAULIC UNIT ALP11
OTHER CASES
NO DIALOGUE WITH THE ABS COMPUTER ALP1
"ABS COMPUTER NOT DETECTED" DURING MULTIPLEX NETWORK TEST
ON CLIPALP12
INTERMITTENT ILLUMINATION OF THE BRAKE, ABS, SERVICE AND STOP
FAULT WARNING LIGHTS AND THE MESSAGE “BRAKE FAILURE” ON THE
INSTRUMENT PANEL WITH NO FAULT CODES IN THE COMPUTERALP13
ABS 8.0X84 4.0
MR-372-J84-38C000$858_eng.mif
Page 53 of 64

ANTI-LOCK BRAKING SYSTEM
Diagnostic - Fault finding chart
38C
38C - 53V2 MR-372-J84-38C000$924_eng.mif
BOSCH ABS 8.0
Vdiag No.: 0C, 0D, 0E, 0F
ALP3 Pull
NOTESOnly consult 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 lit, as the brake limiter
function is no longer guaranteed to operate correctly.
Carry out a road test with the ABS thus out of order.
Is the fault still present under these conditions?
NO
Raise the vehicle so that you can rotate the wheels
and check:
Possible inversion when connecting the speed
sensors.
Possible inversion of pipes on the hydraulic unit.
To perform these tests, refer to and apply the
procedures defined in ALP2. Check the condition
and conformity of the ABS targets. Also check the
sensor/target air gap by rotating each front and rear
wheel one revolution. If the fault is still present,
contact the Techline.
YESIf 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.
AFTER REPAIRClear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS8.0_V0C_ALP03 /ABS8.0_V0D_ALP03/ABS8.0_V0E_ALP03/ABS8.0_V0F_ALP03 ABS 8.0X84 3.0
Page 54 of 64

ANTI-LOCK BRAKING SYSTEM
Diagnostic - Fault finding chart
38C
38C - 54V2 MR-372-J84-38C000$924_eng.mif
BOSCH ABS 8.0
Vdiag No.: 0C, 0D, 0E, 0F
ALP4 Drift
NOTESOnly consult 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 lit, as the brake limiter
function is no longer guaranteed to operate correctly.
Carry out a road test with the ABS thus out of order.
Is the fault still present under these conditions?
NO
Normal behaviour linked to the system operation
during the regulation phase, mainly on surfaces with
uneven grip or which are poorly laid.
YESRoad 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.
AFTER REPAIRClear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS8.0_V0C_ALP04 /ABS8.0_V0D_ALP04/ABS8.0_V0E_ALP04/ABS8.0_V0F_ALP04 ABS 8.0X84 3.0
Page 55 of 64

ANTI-LOCK BRAKING SYSTEM
Diagnostic - Fault finding chart
38C
38C - 55V2 MR-372-J84-38C000$924_eng.mif
BOSCH ABS 8.0
Vdiag No.: 0C, 0D, 0E, 0F
ALP5Unexpected ABS operation at low speeds and slight pedal
pressure
NOTESOnly consult this customer complaint after a complete check with the diagnostic tool.
Warning: the ABS is sensitive on slippery surfaces (ice, wet tiles, etc.).
It is possible to feel brake pedal vibrations which are associated with the reaction of the system in particular
circumstances, such as:
crossing rumble strips,
tight cornering with lifting of the inside rear wheel.
These vibrations may be linked to simple brake limiter activation, when the pressure on the rear axle is limited.
If the fault is different, check the speed sensor connectors (micro-breaks) as well as the air gaps.
AFTER REPAIRClear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS8.0_V0C_ALP05 /ABS8.0_V0D_ALP05/ABS8.0_V0E_ALP05/ABS8.0_V0F_ALP05 ABS 8.0X84 3.0
Page 63 of 64

ANTI-LOCK BRAKING SYSTEM
Diagnostic - Fault finding chart
38C
38C - 63V2 MR-372-J84-38C000$924_eng.mif
BOSCH ABS 8.0
Vdiag No.: 0C, 0D, 0E, 0F
ABS8.0_V0C_ALP13 /ABS8.0_V0D_ALP13/ABS8.0_V0E_ALP13/ABS8.0_V0F_ALP13
ALP 13Intermittent illumination of the brake, ABS, SERVICE and STOP
fault warning lights and the message “brake failure” on the
instrument panel with no fault codes in the computer
NOTESOnly consult this customer complaint after a complete check with the diagnostic
tool.
Check the condition and connection of the
battery terminals.
Is the battery in good condition?
YES
Check the 50A power fuse in position 5 on
the power fuse board. Check fuse F13 (25A)
on the UPC and the correct locking of the
grey 4-track PPH1 connector (Vdiag 44) or
the 25A fuse F8 on the UPC and the correct
locking of the black 6-track CM connector
(Vdiag 48 or higher).
Are the fuses and connectors correct?
YES
Check the connection and condition of the tab
1 red wire of the grey connector.
Is the connector correct?
YES
NOClean the battery terminals.
NOIf the connector is faulty and there is a repair
procedure (see Technical Note 6015A,
Electrical wiring repair, Wiring: Precautions
for repair), repair the connector, otherwise
replace the wiring.
Replace any faulty fuses. Switch on the ignition
again.
Is the replaced fuse or fuses correct?
NO
Check the insulation to earth between:
–fuse 50A and track 2 of the computer
–fuse 25A and track 3 of the computer
Are the connections correct?
NO YES
Contact the Techline.
If the connection(s) are faulty and there is a repair method
(see Technical Note 6015A, Repairing electrical wiring,
Wiring: Precautions for repair), repair the wiring, otherwise
replace it.
NO
If the connector is faulty and there is a repair method (see Technical
Note 6015A, Repairing electrical wiring, Wiring: Precautions for repair),
repair the connector, otherwise replace the wiring.
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.