38C-3
MR-413-X44-38C000$047_eng.mif
V1
ANTI-LOCK BRAKING SYSTEM
Fault finding - Introduction
MK70 ABS
Vdiag No: 04
38C
3. REMINDERS
Procedure
To run diagnostics on the vehicle computers, switch on the ignition using the key.
Faults
Faults are declared as either present or stored (depending on whether they appeared in a certain context and have
disappeared since, or whether they remain present but have not been diagnosed within the current context).
The present or stored status of faults should be taken into consideration when the diagnostic tool is switched on
after the + after ignition feed (without any system components being active).
For a present fault, apply the procedure described in the Interpretation of faults section.
For a stored fault, note the faults displayed and apply the instructions in the Notes section.
If the fault is confirmed when the instructions in the Notes section are applied, the fault is present. Deal with the
fault.
If the fault is not confirmed, check:
–the electrical lines which correspond to the fault,
–the connectors on these lines (corrosion, bent pins, etc.),
–the resistance of the component detected as faulty,
–the condition of the wires (melted or split insulation, wear).
Conformity check
The aim of the conformity check is to check statuses and parameters that do not produce a fault display on the
diagnostic tool when they are inconsistent. Therefore, this stage is used to:
–carry out fault finding on faults that do not have a fault display, and which may correspond to a customer
complaint.
–check that the system is operating correctly and that there is no risk of a fault recurring after repairs.
This section gives the fault finding procedures for statuses and parameters and the conditions for checking them.
If a status is not behaving normally or a parameter is outside the permitted tolerance values, consult the
corresponding fault finding page.
Customer complaints - Fault finding chart
If the test with the diagnostic tool is OK but the customer complaint is still present, the fault should be processed by
customer complaint.
A summary of the overall procedure to follow is provided on the following page in the
form of a flow chart.
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38C
ANTI-LOCK BRAKING SYSTEM
Diagnostics - Replacing parts
REPLACING THE COMPUTER
When replacing the computer (see MR411 Mechanical systems, 38C, Brake computer, removal - refitting), apply
the following procedure:
–switch off the ignition,
–replace the computer,
–enter the VIN number using command VP001 "Write VIN",
–configure the tachometric index with command VP007 "Tachometric index",
–configure the vehicle parameters with command VP004 "Vehicle parameters",
–configure the gearbox type fitted to the vehicle with command CF079 "Gearbox type",
–enter the After-Sales date with command VP006 "Enter last After-Sales operation date",
–perform a road test followed by a fault reading to confirm that the system is operating correctly.
MK70 ABS
Vdiag No: 04
MR-413-X44-38C000$329_eng.mif
38C-13
MR-413-X44-38C000$376_eng.mif
V1
38C
ANTI-LOCK BRAKING SYSTEM
Diagnostics - Configuration and Programming
SETTINGS
VP001: Enter VIN.
This command allows the vehicle identification number to be entered into the computer.
Use this command each time the computer is replaced. The VIN (VF...) is engraved on the manufacturer's
plate on the front right-hand door pillar and stamped on the body under the windscreen on the left-hand
side.
VP004: Vehicle parameters.
This command configures the engine type configuration, the braking definition and the body type.
Select command VP004 on the diagnostic tool.
VP006: Write last After Sales operation date.
Whenever the ABS system is worked on in the shop, the date must be entered.
Select command VP006 "Write date of last After-Sales operation" on the diagnostic tool.
Enter the operation date with the tool keyboard.
VP007: Tachometric index.
This command is used to program the computer memory with the index required to calculate vehicle speed
from the speed at which the wheels turn.
The MK70 ABS computer supplies the vehicle speed signal to all areas where this information is needed
(instrument panel, engine management, etc.). This vehicle speed signal replaces 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 command VP007 "Tachometric index" on the diagnostic tool.
Once the number has been entered using the VP007 command, delete the fault in the computer memory and then
switch off the ignition. Use parameter PR030 Tachometric index to check that the index entered has been correctly
registered.
CONFIGURATIONS
CF079: Gearbox type.
Use this command to configure the gearbox type fitted on the vehicle.
OTHER COMMANDS
LC008: Gearbox type.
This command tells you the gearbox type configured on the vehicle. Note:
The vehicle speed is delivered by wire (connection 47F) to the radio, to the electric power-assisted steering, to
the electric sunroof and by the multiplex network for the other computers.
MK70 ABS
Vdiag No: 04
MR-413-X44-38C000$376_eng.mif
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MR-413-X44-38C000$470_eng.mif
V1
MK70 ABS
Vdiag No: 04ANTI-LOCK BRAKING SYSTEM
Fault finding - Interpretation of faults38C
DF006
PRESENT
OR
STOREDFRONT LEFT-HAND WHEEL SPEED SENSOR CIRCUIT
1.DEF: Fault on the wheel speed sensor circuit
NOTESConditions for applying the fault finding procedure to stored faults:
Follow the fault finding procedure described below for DF006 stored.
Use the Technical Note wiring diagram for New Twingo.
DF006 PRESENT
NOTESNone
Check the connection and condition (possible damage to the wiring) of the connector of component 1094.
Check the connection and condition (possible damage to the wiring) of the connector of component 153.
If the connector is faulty (see Technical Note 6015A, Repairing electrical wiring, wiring: Precautions for
repair), repair the connector, otherwise replace the wiring.
Check for a voltage of approximately 12 V between the two connections of component 153 near component 1094.
Is the voltage measured correct?
YES
Swap the 2 front wheel speed sensors over. Clear the computer fault memory.
Switch off the ignition. Switch on the ignition again.
If the fault initially declared as DF006 Front left wheel speed sensor circuit has
become a present DF026 Front right wheel speed sensor circuit, replace the wheel
speed sensor.
If the fault remains on the same side, the wiring between the computer and the sensor is
faulty.
Check insulation and continuity of connections 4C and 4E between
components 153 and 1094.
Also check the insulation between these 2 connections.
If the connection or connections are faulty (see Technical Note 6015A, Electrical
wiring repair, Wiring: Precautions for repair), repair the connectors or wiring,
otherwise replace the wiring.
Check insulation and continuity of connections 4C and 4E between
components 153 and 1094.
Also check the insulation between these 2 connections.
If the connection or connections are faulty (see Technical Note 6015A, Electrical
wiring repair, Wiring: Precautions for repair), repair the connectors or wiring,
otherwise replace the wiring.
If the fault is still present, contact the Techline.
NO
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
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ANTI-LOCK BRAKING SYSTEM
Fault finding - Interpretation of faults
MK70 ABS
Vdiag No: 04
38C
DF008
PRESENT
OR
STOREDFRONT LEFT-HAND WHEEL SPEED SENSOR SIGNAL
1.DEF: Inconsistent sensor signal
2.DEF: No vehicle speed signal
3.DEF: Inconsistent vehicle speed
NOTESPriorities when dealing with a number of faults:
Deal with fault DF006 Front left wheel speed sensor circuit first if it is present.
Conditions for applying the fault finding procedure to stored faults:
The fault is declared present during a road test (in excess of 12 mph (20 km/h)
for 2 minutes).
Check the condition of the axle assemblies (impacts, damage, etc.) and the conformity and good condition of the
tyres.
Check that the braking system (condition of brake pads, sealing, sticking, bleed, bearing clearance, etc.) is in
good condition.
Visually inspect the condition of the target (for clogging, metallic contamination, bearing grease, etc.) and clean
using compressed air if necessary.
If there is a lot of grease on the target, contact the Techline.
Check that the wheel speed sensor mounting is in good condition.
Check the conformity of the target (condition, number of teeth = 48) using the special command SC001 Check
target teeth.
If there is non-conformity, replace the target.
Check the connection and condition (possible damage to the wiring) of the connector of component 1094.
Check the connection and condition (possible damage to the wiring) of the connector of component 153.
If the connector is faulty (see Technical Note 6015A, Repairing electrical wiring, wiring: Precautions for
repair), repair the connector, otherwise replace the wiring.
Check for a voltage of approximately 12 V between the two connections of the connector of component 153 near
component 1094.
If a 12 V feed is not present, contact the Techline.
If all the checks are in order, swap the 2 front wheel speed sensors. Clear the computer fault memory.
Switch off the ignition. Switch the ignition back on and carry out a road test.
If a fault, which was initially registered as DF008 Front left-hand wheel speed sensor signal has become
present DF028 Front right-hand wheel speed sensor signal, replace the wheel speed sensor
(see MR 411 Mechanical systems, 38C, Wheel speed sensor: Removal - Refitting).
If the fault stays on the same side, the target is faulty, replace the active sensor bearing.
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS_V04_DF008
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ANTI-LOCK BRAKING SYSTEM
Fault finding - Interpretation of faults
MK70 ABS
Vdiag No: 04
38C
DF009
PRESENT
OR
STOREDREAR LEFT-HAND WHEEL SPEED SENSOR SIGNAL
1.DEF: Inconsistent sensor signal
2.DEF: No vehicle speed signal
3.DEF: Inconsistent vehicle speed
NOTESPriorities when dealing with a number of faults:
Deal with fault DF007 Rear left-hand wheel speed sensor circuit first if it is present.
Conditions for applying the fault finding procedure to stored faults:
The fault is declared present during a road test (in excess of 12 mph (20 km/h)
for 2 minutes).
Check the condition of the axle assemblies (impacts, damage, etc.) and the conformity and good condition of the
tyres.
Check that the braking system (condition of brake pads, sealing, sticking, bleed, bearing clearance, etc.) is in
good condition.
Visually inspect the condition of the target (for clogging, metallic contamination, bearing grease, etc.) and clean
using compressed air if necessary.
If there is a lot of grease on the target, contact the Techline.
Check that the wheel speed sensor mounting is in good condition.
Check the conformity of the target (condition, number of teeth = 48) using the special command SC001 Check
target teeth.
If there is non-conformity, replace the target.
Check the connection and condition (possible damage to the wiring) of the connector of component 1094.
Check the connection and condition (possible damage to the wiring) of the connector of component 151.
If the connector is faulty (see Technical Note 6015A, Repairing electrical wiring, wiring: Precautions for
repair), repair the connector, otherwise replace the wiring.
Check for a voltage of approximately 12 V between the two connections of the connector of component 151 near
component 1094.
If a 12 V feed is not present, contact the Techline.
If all the checks are in order, swap the 2 rear wheel brake drums. Clear the computer fault memory.
Switch off the ignition. Switch the ignition back on and carry out a road test.
If the fault initially declared as DF009 "Rear left-hand wheel speed sensor signal" has become present DF029
"Rear right-hand wheel speed sensor signal", replace the complete drum (see MR411 Mechanical systems,
33A, Rear axle components).
If the fault remains on the same side, replace the speed sensor (see MR411 Mechanical systems, 38C Wheel
speed sensor, Removal - Refitting).
Important, do not forget to refit the drums to the correct wheels.
If the fault is still present, contact the Techline.
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS_V04_DF009
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MR-413-X44-38C000$470_eng.mif
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ANTI-LOCK BRAKING SYSTEM
Fault finding - Interpretation of faults
MK70 ABS
Vdiag No: 04
38C
DF017
PRESENT
OR
STOREDCOMPUTER
1.DEF: Computer fault
NOTESConditions for applying the fault finding procedure to stored faults:
Apply the fault finding procedure whether the fault is present or stored.
Check the connection and condition (possible damage to the wiring) of the connector of component 1094.
If the connector is faulty (see Technical Note 6015A, Repairing electrical wiring, wiring: Precautions for
repair), repair the connector, otherwise replace the wiring.
Clear the computer fault memory, exit the fault finding and switch off the ignition.
Carry out another check using the diagnostic tool.
If the fault is still present, contact the Techline.
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
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ANTI-LOCK BRAKING SYSTEM
Fault finding - Interpretation of faults
MK70 ABS
Vdiag No: 04
38C
DF020
PRESENT
TACHOMETRIC INDEX PROGRAMMING
1.DEF: Tachometric index not programmed
NOTESNone
The MK70 ABS computer with the tachometric function supplies the vehicle speed signal to all areas where this
information is needed (instrument panel, engine management, etc.).
This vehicle speed signal replaces 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 command VP007 "TACHOMETRIC INDEX" using the diagnostic tool.
Once the index has been entered using the VP007 command, clear the computer fault memory and then switch
off the ignition.
Use the PR030 parameter to check that the index has been stored correctly.
If the fault is still present, contact the Techline.
AFTER REPAIRClear the computer fault memory.
Carry out a road test followed by another check with the diagnostic tool.
ABS_V04_DF020P