Page 54 of 76

38C-54
MR-413-X44-38C000$658_eng.mif
V1
MK70 ABS
Vdiag No: 04ANTI-LOCK BRAKING SYSTEM
Fault finding - Interpretation of statuses38C
ET017
CONTINUED 1
Connectors of components 645, 172, 173, 639 and 1094, intermediate connectors
R107 and R15 and connector of component 119 (if present on the vehicle)
disconnected from connection 65A:
–Check the insulation of connection 65A between component 160 and
intermediate connector R107.
–Check the insulation of connection 65A between component 172 and
intermediate connector R107.
–Check the insulation of connection 65A between component 173 and
intermediate connector R107.
–Check the insulation of connection 65A between intermediate connectors R107
and R15.
–Check the insulation of connection 65A between component 639 and
intermediate connector R15.
–Check the insulation of connection 65A between component 645 and
intermediate connector R107.
If the connector is faulty (see NT6015, Repairing electrical wiring, wiring:
Precaution for repairs), repair the connector, otherwise replace the wiring.
–Check for + 12 V after ignition feed on connection AP10 of component 1016 to
earth MAH.
If the checks reveal no faults, carry out a check of each component associated with
connection 65A and AP10 (short circuits).
Check the condition and positioning of the F5 5A fuse (see MR411 Mechanical
systems, 81C, Fuses: 16A).
–Check the condition, mounting and adjustment of the brake light switch and the
conformity of the bulbs.
–Remove the brake light switch and check that it is operating correctly:
Connection continuity Connection insulation
Switch pressed
(Brake pedal released)AP10 and 5A AP10 and 65A
Switch released
(Brake pedal
depressed)AP10 and 65A AP10 and 5A
–Replace the switch if necessary.
Connectors of components 645, 172, 173, 639 and 1094, intermediate
connectors R107 and R15 and connector of component 119 (if present on the vehicle)
disconnected from connection 65A
–Check the insulation of connection 65A between component 160 and
intermediate connector R107.
STATUS
DEPRESSED:
Brake pedal
released
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
Page 64 of 76
38C-64
MR-413-X44-38C000$893_eng.mif
V1
38C
ANTI-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 ALP 2
PULLING ALP 3
DRIFT ALP 4
UNEXPECTED ABS OPERATION AT LOW SPEEDS AND SLIGHT PEDAL
PRESSURE ALP 5
UNEXPECTED ABS OPERATION ON A POOR ROAD SURFACE ALP 6
UNEXPECTED ABS OPERATION WHEN SPECIAL EQUIPMENT
USED (CAR PHONE, CB, ETC.) ALP 7
EXTENSION OF BRAKE PEDAL TRAVEL FOLLOWING
REGULATION PHASE (WITH LEAKING PEDAL WHEN STARTING
REGULATION PHASE)ALP 8
SPONGY PEDAL ALP 9
BRAKE PEDAL VIBRATION ALP 10
NOISES FROM THE PUMP, PIPES OR HYDRAULIC UNIT ALP 11
OTHER CASES
NO DIALOGUE WITH THE ABS COMPUTER ALP 1
MK70 ABS
Vdiag No: 04
MR-413-X44-38C000$893_eng.mif
Page 68 of 76

38C-68
MR-413-X44-38C000$940_eng.mif
V1
MK70 ABS
Vdiag No: 04ANTI-LOCK BRAKING SYSTEM
Fault finding - Fault Finding Chart38C
ALP 3 Pull
NOTESOnly consult this customer complaint after a complete check with the diagnostic tool.
Check the conformity of the mechanical components.
Disconnect one wheel speed sensor.
Start the engine and ensure that only the ABS
system fault warning light comes on. Do not drive
the vehicle if the brake fault warning light is also lit,
as the "EBD" (brake limiter) function is no longer
ensured.
Carry out a road test with the ABS thus out of order.
Is the customer complaint 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.
For these two tests, refer to and apply the
procedures described in ALP 2.
Check the condition and conformity of the ABS
targets.
If necessary, replace the targets.
If the fault is still present replace the hydraulic unit.
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 fault memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS_V04_ALP3
Page 69 of 76

38C-69
MR-413-X44-38C000$940_eng.mif
V1
MK70 ABS
Vdiag No: 04ANTI-LOCK BRAKING SYSTEM
Fault finding - Fault Finding Chart38C
ALP 4 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
system fault warning light comes on. Do not drive
the vehicle if the brake fault warning light is also lit,
as the "EBD" (brake limiter) function is no longer
ensured.
Carry out a road test with the ABS thus out of order.
Is the customer complaint 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 fault memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS_V04_ALP4
Page 70 of 76
38C-70
MR-413-X44-38C000$940_eng.mif
V1
ANTI-LOCK BRAKING SYSTEM
Fault finding - Fault Finding Chart
MK70 ABS
Vdiag No: 04
38C
ALP 5Unexpected ABS operation at low speed and with
slight pedal pressure
NOTESOnly consult this customer complaint after a complete check with the diagnostic tool.
IMPORTANT: ABS regulation is sensitive on slippery surfaces (ice, wet cobbled
streets, etc.).
Check the conformity of the mechanical components.
Brake pedal vibrations may be felt which are connected to the system behaviour in particular situations:
–Crossing speed bumps.
–Tight cornering with lifting of the inside rear wheel.
These vibrations may be linked simply to "EBD" (brake limiter) activation, when the pressure on the rear axle is
limited.
If the fault relates to something else, check the speed sensor connectors (micro-breaks) as well as the targets.
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS_V04_ALP5