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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS
Fault finding - Interpretation of XR25 bargraphs
38
ABS BOSCH
5.3
Bargraph 1, right hand side extinguished
Code present
1
None. NOTES
Fiche n° 53
Check that the XR25 kit is not the cause of the fault by trying to communicate with the computer of
another vehicle. If the XR25 kit is not at fault and it will not communicate with any other computer in the
same vehicle, it is possible that a faulty computer is corrupting fault finding lines K and L . Locate this
computer by disconnecting the lines one by one.
Check that the ISO interface is correctly in position S8 and that you are using the most recent XR25
cassette and the correct access code.
Check the battery voltage and carry out the necessary operations to obtain the correct voltage(9.4Volts<
U battery<17.4Volts)
Check the presence and condition of the ABS fuse on the connection unit of the passenger compartment
(10A).
Check the connection of the computer connector and the condition of its connection.
Check the connection and condition of the connection at the R36 dashboard / ABS connection.
Check the ABS earth wires (tighten the two earth screws above the ABS assembly).
Check that the computer is correctly fed :
-earth on track 19 of the 31 track connector,
-+ after ignition feed on track 15 of the 31track connector.
Check that the diagnostic socket is correctly fed :
-+ before ignition feed on track 16,
-earth on track 5.
Check the continuity and insulation of the lines in the diagnostic socket / ABS computer connection:
- between track 12 of the computer connector and track 15 of the diagnostic socket,
- between track 11 of the computer connector and track 7 of the diagnostic socket.
If dialogue is still not established after these tests, replace the ABS computer.,
When communication is established, deal with any fault bargraphs which may be
illuminated. AFTER REPAIR
38-4
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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS
Fault finding - Interpretation of XR25 bargraphs
38
ABS BOSCH
5.3
After replacing the computer, carry out another XR25 test.AFTER REPAIR
Bargraph 1 left hand side illuminated
Power supply/computer
1
None.
NOTES
Fiche n° 53
Erase the computer memory, exit the fault finding (G13*) and switch off the ignition.
Carry out a new XR25 test. If the "power supply / computer" fault persists, replace the ABS computer.
Check the condition and position of the 60A ABS fuse in the engine connection unit (white mounting).
Ensure continuity between this fuse and tracks 17 and 18 of the computer connector (presence of positive
before ignition feed on both tracks). Check the tightness and condition of the battery terminals.
Check the connections on the 31 track connector of the ABS computer.
Check the ABS earths (above the hydraulic assembly) and visually check all the ABS wiring.
38-5
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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS
Fault finding - Interpretation of XR25 bargraphs
38
ABS BOSCH
5.3
Erase computer memory(GO**).
Carry out a road test followed by a check with the XR25 kit.AFTER REPAIR
Bargraphs 2, 3, 4 or 5 right or left hand side flashing
Solenoid valve circuit
Even if present at time of testing, these faults will always be declared by a
flashing bargraph.
To confirm their presence and therefore the need to apply the fault finding
described below start command G20*. The fault is present if the bargraph
appears illuminated at the end of the command.
If bargraph 11 left hand side is also illuminated, deal with bargraph 11 left hand
side as a priority.
NOTES
Fiche n° 532 - 3 - 4 - 5
Check the ABS earths (tightening of the two screws above the hydraulic assembly).
Check the condition and position of the 60A ABS fuse in the engine connection unit (white mounting).
Check the connection and condition of the connections on the 31 track connector of the computer.
Erase the computer memory, exit the fault finding mode(G13*) switch off the ignition.
Switch on the ignition and carry out a new test with the XR25 kit, using command G20*.
If the fault "solenoid valve circuit"reappears, replace the ABS computer.
38-6
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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS
Fault finding - Interpretation of XR25 bargraphs
38
ABS BOSCH
5.3
Erase computer memory(GO**).
Carry out a road test followed by a check with the XR25 kit.AFTER REPAIR
Bargraph 11 left hand side illuminated
Solenoid valve power supply fault
11Fiche n° 53
If all the checks are correct, reconnect the computer then erase its memory with command G0**.
Leave fault finding mode(G13*) and carry out a road test. Replace the computer if the fault reappears.
Carry out operations necessary for obtaining correct voltage between tracks 19 and 17/18 of the 31-track
ABS computer connector (9.4 volts < correct voltage < 17.4 volts) :
- Check tightness and condition of battery terminals.
- Check the 60A fuse in the engine connection unit (white base).
- Ensure continuity between the 60A fuse and tracks 17 and 18 of the computer connector.
- Check the ABS earths (tightening of the two earth bolts above the hydraulic assembly).
- Check/ ensure continuity between the ABS earth and track 19 of the computer connector.
None.
NOTES
38-14
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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEMS
Fault finding - Interpretation of XR25 bargraphs
38
ABS BOSCH
5.3
AFTER REPAIR
13Fiche n° 53
Bargraph 13 left hand side extinguished, brake pedal depressed
Carry out checks only if illumination of the bargraph is not consistent with the
pedal position. NOTES
Bargraph 13 right and left
Brake pedalIlluminated on left hand side if pedal depressed.
Illuminated on right hand side if pedal not depressed.
BG 13 right remains permanently illuminated.
If brake lights are operating
:
- Ensure continuity between dashboard / rear left R2 connector on track 7 and track 14 of the ABS
computer connector .
Dashboard / ABS R36 intermediate connector (track 8).
If brake lights are not operating
:
- Check condition and adjustment of brake light switch as well as the 15A fuse for the brake lights (in
the passenger compartment connection unit). Replace if necessary.
- Disconnect the brake light switch, then check / ensure presence of + after ignition feed on track A3
of the connector
- Check operation of brake light switch (closed contact between tracks A3 and B1).
- Check and ensure continuity between track B1 of the brake light switch connector and the dashboard
/ rear left hand side R2 connector on track 7.
Bargraph 13 permanently illuminated on left hand side
- Check the condition and adjustment of the brake light switch. Replace if necessary.
- Check the operation of the brake light switch contact (closed contact between tracks A3 and B1).
Replace the brake light switch if there is permanent continuity between the two tracks.
- Check and ensure insulation from 12 volts of the connection between track B1 of the brake light
switch connector and track 14 of the ABS computer connector .
Intermediate connectors : Dashboard / ABS R36 on track 8.
Dashboard / rear left hand side R2 on track 7.
Carry out a road test followed by a check with the XR25 kit.
38-17
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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEM
Fault finding - Fault chart 38
ABS BOSCH
5.3
AFTER REPAIR Carry out a road test, then a check with the XR25 kit.
yes
ABS WARNING LIGHT DOES NOT ILLUMINATE FOR 3
SECONDS WHEN IGNITION SWITCHED ONFault chart 1
Only consult this section after a complete check with the XR25 kit.NOTES
Check condition of ABS warning light bulb
and its power supply.
Ensure continuity of connection between
track 21 of the computer connector and the
warning light (track 3 of the black
instrument panel connector).
If fault persists, check the instrument panel
operation.
Carry out an inspection of the connections
on the 31 track connector.
Replace the computer if the fault persists.
no
Check the 15A instrument panel fuse on the
passenger compartment connection unit
(if the problem affects all instrument panel
operations).
Turn off the ignition.
Disconnect the computer, then switch on
the ignition again.
Does the warning light illuminate?
38-21
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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEM
Fault finding - Fault chart 38
ABS BOSCH
5.3
AFTER REPAIR Carry out a road test, then a check with the XR25 kit.
yes
PULLINGFault chart 5
Only consult this section after a complete check with the XR25 kit.NOTES
Lift the vehicle so the wheels can be turned
and check for :
- a possible incorrect connection in the
speed sensors,
- a possible incorrect connection of the
hydraulic assembly piping.
For these two checks, consult and apply the
methods defined in Fault Chart 4.Check the
condition of the ABS targets and that they
conform. Also check the sensor/ target air
gap by rotating each wheel.
If the fault persists, replace the hydraulic
assembly.
If the pedal travel is relatively long, bleed
the brake circuit.
If it is normal, check the tyre pressure, the
front axle assembly
or possibly for leaks in the circuit.
no
Remove the 10A ABS fuse on the passenger
compartment connection unit and carry out
a road test with the ABS non-operational.
Does the fault persist under these
conditions?
38-25
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B76531.0
ELECTRONICALLY CONTROLLED HYDRAULIC SYSTEM
Fault finding - Fault chart 38
ABS BOSCH
5.3
AFTER REPAIR Carry out a road test, then a check with the XR25 kit.
yes
WANDERINGFault chart 6
Remove the 10A ABS fuse in the passenger
compartment connection unit and carry out
a road test with ABS non-operational.
Does the fault persist under these
conditions?
Only consult this section after a complete check with the XR25 kit.NOTES
Normal behaviour linked to system
operation in the regulation phase
essentially because of asymmetrical grip or
poor road surface.
Handling fault not linked to ABS system.
Check the condition and conformity of
brake linings, check tyre pressures, front
axle assembly, ...
no
38-26