Page 52 of 363

JF5111.0
INJECTION
Fault finding - Introduction
17
E7J 780
engine
XR25 CHECKING STATUSES AND PARAMETERS
The status and parameter check is aimed at checking the statuses and parameters which do not illuminate
any fault bargraphs if they are outside of permitted tolerance values . This phase allows :
- Faults to be found without the illumination of fault bargraphs which may correspond to a customer
complaint (example : absence of no load information causing an unstable idle speed).
- The correct operation of the injection to be checked and the risk of faults appearing shortly after the
repair to be eliminated.
This section contains fault-finding for statuses and parameters, under their test conditions
(example : fault finding for # 01 ignition on and fault finding for # 01 engine running).
If a status does not operate normally or a parameter is outside of permitted tolerance values, consult the
fault-finding page indicated in the "Fault-finding" column.
XR25 CHECK CORRECT
If the XR25 check is correct, but the customer complaint persists, the problem must be dealt with through
customer complaints.
Treatment of customer complaints
This section has fault charts, which suggest a series of possible causes of the problem.
These lines of enquiry must only be used in the following cases :
- No fault bargraph appears on the XR25.
- No faults are detected during the checking of statuses and parameters.
- The vehicle is not operating correctly
POST-REPAIR CHECK
This operation is a simple check of the repair (by a command, or by an XR25 command mode ...).
This makes it possible to check that the system upon which the intervention has been carried out is correct
electrically.
It is an introduction to the road test.
ROAD TEST
A road test is essential in order to guarantee the correct operation of the vehicle and to test the quality of the
repair. Its role is to make sure that no faults occur (or will occur) when driving.
In order to be significant, the road test is subject to special driving conditions.
17-4
Page 57 of 363

Connect the bornier in place of the computer and check the insulation and continuity of the line:
Computer 2 Earth
Computer 3 Earth
Computer 11 7 Diagnostic socket
Computer 38 15 Diagnostic socket
Computer 24 Fuse F6 15 A
Computer 32 Fuse F3 5 A
Repair.
JF5111.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
E7J 780
engine
Erase the computer memory using G0**.
Try to start the engine. Switch the ignition on, then deal with the other faults.
Remember to carry out a status and parameter check.AFTER REPAIR
Bargraph 1 RH side extinguishedFiche n° 27 side 1/2
XR25 CIRCUIT
XR25 aid:No connection, CO, CC-, CC+
1
This bargraph must be illuminated for fault findingNOTES
Test the XR25 on another vehicle.
Check:
- the injection, engine and passenger compartment fuses,
- the connection between the XR25 and the diagnostic socket,
- the position of the ISO selector (S8),
- the conformity of the cassette.
Repair if necessary.
Check:
- the presence of + 12 V on track 16 and earth on track 5 of the diagnostic socket,
- that the XR25 cable is in good condition.
Repair if necessary.
17-9
Page 58 of 363
JF5111.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
E7J 780
engine
Erase the computer memory using G0**.
Try to start the engine. Switch the ignition on, then deal with the other faults.
Remember to carry out a status and parameter check.AFTER REPAIR
Bargraph 2 LH side illuminatedFiche n° 27 side 1/2
COMPUTER CIRCUIT
XR25 aid:Computer faulty
2
NoneNOTES
The computer is incorrect or faulty.
Replace the computer.
17-10
Page 59 of 363
JF5111.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
E7J 780
engine
Erase the computer memory using G0**.
Try to start the engine. Switch the ignition on, then deal with the other faults.
Remember to carry out a status and parameter check.AFTER REPAIR
Bargraph 2 RH side illuminatedFiche n° 27 side 1/2
IMMOBILISER CIRCUIT
XR25 aid:*22 = 1 dEF CO, CC- or CC+ line 37 on the computer
*22 = 2 dEF Refer to the immobiliser fault finding
2
Ignore this bargraph if the vehicle is not fitted with an immobiliser.NOTES
Connect the bornier in place of the computer and check the insulation, continuity and that there is no
interference resistance on the wiring on track 37 of the computer.
Repair if necessary.
If the fault persists, refer to the immobiliser fault finding.
17-11
Page 60 of 363
Connect the bornier in place of the computer and check the insulation and continuity of the line:
Computer 20 2 Air temperature sensor
Computer 46 1 Air temperature sensor
Repair if necessary.
JF5111.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
E7J 780
engine
Erase the computer memory using G0**.
Try to start the engine. Switch the ignition on, then deal with the other faults.
Remember to carry out a status and parameter check.AFTER REPAIR
Bargraph 3 LH side illuminatedFiche n° 27 side 1/2
AIR TEMPERATURE SENSOR CIRCUIT
XR25 aid:CO, CC- or CC+line 20 or 46
3
If BG 6RH is also illuminated, check line 46 of the computer.NOTES
Check the resistance of the sensor. Replace it if necessary.
The fault persists! Replace the injection computer.
IMPORTANT: The computer has probably been damaged by an electric shock. The cause of the damage
must be found before fitting a new computer.
17-12
Page 61 of 363

Connect the bornier in place of the computer and check the insulation and continuity of the line:
Computer 17 C Oxygen sensor
Repair if necessary.
JF5111.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
E7J 780
engine
Turn the engine, switch the ignition on and erase the computer memory using
G0**. Try to start the engine. Switch the ignition on, then deal with the other
faults. Remember to carry out a status and parameter check.AFTER REPAIR
Bargraph 3 RH side illuminated or flashingFiche n° 27 side 1/2
OXYGEN SENSOR CIRCUIT
XR25 aid:CO, CC- or CC+line 17
3
If BG 3RH is flashing, increase the engine speed to 2500 rpm for 5 minutes
If BG3RH becomes permanently illuminated, deal with the fault.
NOTES
Check the connection and the condition of the connector on the oxygen sensor.
Check, ignition on during the timed phase, for :
-earth on track B of the oxygen sensor,
-+ 12 V after the fuel pump relay on track A of the oxygen sensor.
Repair if necessary.
The fault persists. Replace the oxygen sensor.
The fault persists! Replace the injection computer.
IMPORTANT: The computer has probably been damaged by an electric shock. The cause of the damage
must be found before fitting a new computer.
17-13
Page 62 of 363
Connect the bornier in place of the computer and check the insulation and continuity of the line:
Computer 44 B1 Coolant temperature sensor
Computer 15 B2 Coolant temperature sensor
Repair if necessary.
JF5111.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
E7J 780
engine
Erase the computer memory using G0**.
Try to start the engine. Switch the ignition on, then deal with the other faults.
Remember to carry out a status and parameter check.AFTER REPAIR
Bargraph 4 LH side illuminatedFiche n° 27 side 1/2
COOLANT TEMPERATURE SENSOR CIRCUIT
XR25 aid:CO, CC- or CC+line 44 or 15
4
If BG 6LH or BG 5LH is also illuminated, check line 44 of the computer.NOTES
The fault persists! Replace the injection computer.
IMPORTANT: The computer has probably been damaged by an electric shock. The cause of the damage
must be found before fitting a new computer.
Check the resistance of the sensor. Replace it if necessary.
17-14
Page 63 of 363

Connect the bornier in place of the computer and check the insulation, continuity and that there is no
interference resistance on the line:
Computer 12 B1 Vehicle speed sensor
Repair if necessary.
JF5111.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
E7J 780
engine
Erase the computer memory using G0**.
Try to start the engine. Switch the ignition on, then deal with the other faults.
Remember to carry out a status and parameter check.AFTER REPAIR
Bargraph 4 RH side illuminated or flashingFiche n° 27 side 1/2
VEHICLE SPEED CIRCUIT
XR25 aid:CO, CC- or CC+ line 12
4
Carry out a road test if BG 4RH is flashingNOTES
Check on the vehicle speed sensor for:
-earth on track B2,
-+ 12 after ignition feed on track A.
Repair if necessary.
The fault persists! Replace the sensor.
The fault persists! Replace the injection computer.
IMPORTANT: The computer has probably been damaged by an electric shock. The cause of the damage
must be found before fitting a new computer.
Check the sensor is correctly positioned.
17-15