Page 187 of 363

JSA051.0
INJECTION
Fault finding - Checking conformity
17
D7F 710
engine -
35 tracks
Checks to be carried out during a road test.NOTES
Order of
operationsFunction to be
checkedAction Bargraph Display and notes
1 Change to status testG01*
10.NJ
Use fiche n° 27
status test side
2No fault presentEnsure this bargraph is not
flashing, otherwise enter
G02* and turn over the fiche.
IMPORTANT: This bargraph
may flash if the vehicle has no
immobiliser. Ignore this
bargraph if fault bargraph 2 RH
side is illuminated and *22 = 2
dEF.
Repair the faulty component
the erase the memory (G0**)
and return to the status test
(G01*)
3 Canister bleed# 23Canister bleed is authorised
X = variable and > 0.7
4Vehicle speed
information# 18X = vehicle speed read on
speedometer
5 Pinking sensor Vehicle under
load and
engine speed
2000 rpm
# 13
# 15X = variable and not zero
0 ≤ X ≤ 6
(if there is a sensor fault, the
advance is retarded
systematically by 4° , which is
not visible using # 15)
11
20
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Page 192 of 363

JSA052.0
INJECTION
Fault finding - Introduction
17
D7F 710
engine -
55 tracks
DESCRIPTION OF THE FAULT-FINDING PHASES
The process described below is to be carried out in all cases of faults.
XR25 FAULT-CHECKING
This phase is the essential starting point for any intervention on the vehicle.
There are several constraints to the treatment of the bargraphs :
- A priority in the order of treatment when several bargraphs are illuminated.
- The interpretation of a bargraph depending on whether it is constantly illuminated or flashing .
1 - Order of priority
A series of illuminated bargraphs corresponding to the sensors with the same 12 V or having the same
earth, indicates a fault in this source. These priorities are dealt with in the "NOTES" section of the
fault-finding of the bargraph concerned.
2 - Input / output fault bargraphs
a) Illuminated :
The fault is present : treat the fault following the method described in the "INTERPRETATION OF XR25
BARGRAPHS" section.
b) Flashing :
Note the bargraphs displayed on the XR25.
Erase the memory of the computer and attempt to re-illuminate the bargraph: ignition on, idle speed
(or at starter speed) or by means of a road test (the "NOTES" section in the fault finding for the
bargraph concerned may help to determine the conditions under which the bargraph will illuminate).
If the bargraph has re-illuminated (fixed or flashing) :
The fault is present once again. In this case, treat the fault bargraph.
If the bargraph has not re-illuminated, check :
- the electrical lines which correspond to the flashing fault,
- the connectors of these lines (for rust, bent pins...).
- the resistance of the component found to be faulty.
- the cleanliness of the wires (insulation melted or cut, friction..).
NOTE : If the customer complaint does not correspond to the fault bargraph which is flashing
(example : Air temperature sensor fault bargraph flashing, but no customer complaint) ignore
this memorised fault and erase it.
3 - No bargraphs illuminated
If no bargraphs are illuminated on the XR25, carry out a status and parameter check. This may help in
detecting a problem.
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Page 201 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.
JSA052.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
D7F 710
engine -
55 tracks
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 of the computer
3
If BG 6RH is also illuminated, check line 46 of the computer.NOTES
Check the resistance of the sensor. Replace 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.
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Page 202 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.
JSA052.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
D7F 710
engine -
55 tracks
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 flashing Fiche n° 27 side 1/2
OXYGEN SENSOR CIRCUIT
XR25 aid:CO, CC- or CC+line 17 of the computer
CO line 18 of the computer
3
If BG 3RH is flashing, increase the engine speed to 2500rpm for 5 minutes.
If BG 3RH 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.
Check for the presence of earth on track 18 of the injection computer.
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.
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Page 203 of 363

Connect the bornier in place of the computer and check the insulation and continuity of the line:
Computer 44 1 Coolant temperature sensor
Computer 15 2 Coolant temperature sensor
Repair if necessary.
JSA052.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
D7F 710
engine -
55 tracks
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 illuminated Fiche n° 27 side 1/2
COOLANT TEMPERATURE SENSOR CIRCUIT
XR25 aid :CO, CC- or CC+line 44 or 15 of the computer
4
If BG 6LH or BG 5LH is also illuminated , check line 44 of the computer. For certain
faults, BG 4LH is only permanently illuminated when the engine is running.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.
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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.
JSA052.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
D7F 710
engine -
55 tracks
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 flashing Fiche n° 27 side 1/2
VEHICLE SPEED CIRCUIT
XR25 aid:CO, CC- or CC+ line 12 of the computer
4
Carry out a road test if the BG 4RH is flashing.NOTES
Check the sensor is correctly positioned.
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.
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Connect the bornier in place of the computer and check the insulation, continuity and that there is no
interference resistance on the line:
Computer 45 C Pressure sensor
Computer 44 A Pressure sensor
Computer 16 B Pressure sensor
Repair if necessary.
JSA052.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
D7F 710
engine -
55 tracks
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 5LH side illuminatedFiche n° 27 side 1/2
PRESSURE SENSOR CIRCUIT
XR25 aid :CO, CC- or CC+ line 45, 44 or 16 of the computer
5
If BG 6RH is also illuminated, check line 45 of the computer.
If BG 6LH or BG 4LH is also illuminated, check line 44 of the computer.NOTES
Check that the pressure sensor is connected correctly both electrically and pneumatically.
Check the conformity of the pressure sensor pipe (it must not be pierced or blocked...).
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.
The fault persists! Replace the sensor.
17-162
Page 206 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 33 B Target sensor
Computer 34 A Target sensor
Repair if necessary.
JSA052.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
D7F 710
engine -
55 tracks
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 5 RH side illuminated or flashingFiche n° 2 side 1/2
FLYWHEEL SIGNAL CIRCUIT
XR25 aid:*25 = CO.0 =>CO or CC- line 33 or 34 of the computer
*25 = CC.0 =
>CC- line 33 or 34 of the computer
*25 = In =
>sensor incorrectly connected
5
Try to illuminate BG 5RH when the starter is activated.
BG 5RH is often seen to flash if *25 = dEF as its permanent illumination is very
quick. In certain cases, BG 5RH may illuminate then extinguish.
NOTES
Check the resistance of the target sensor.
Replace the sensor if necessary.*25 = CO.0
*25 = CC.0
Check the condition of the flywheel, especially if it has been removed.
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 target sensor has been correctly connected (the sensor connector must
not be inverted).
Repair if necessary.*25 = In
The fault persists! Replace the sensor.
17-163