Page 150 of 363
Order of
operationsFunction to be
checkedAction Bargraph Display and notes Fault finding
1Flywheel signal
sensor StarterIlluminated if TDC
information is detected
DIAG 5
2Fuel pump
G10*Fuel pump should be
heard to operateDIAG 6
3 IgnitionConnect
Optima
StationStarting test.
Complete guide on
Optima StationUse Optima
5800 Station
4Fuel pressureConnect
pressure
gauge to
fuel inlet
and activate
starter
motorPressure gauge must
show
2.5 bars Fuel pressure,
see Workshop
Repair
Manual or
section
5Injector
commandStarterFuel must come out of
the injector
DIAG 11
6Engine
compressionConnect
Optima
StationComplete guide on
Optima StationUse Optima
5800 Station
7 FlywheelConnect
Optima
StationOscilloscope.
Complete guide on
Optima StationUse Optima
5800 Station
JSA051.0
INJECTION
Fault finding - Status and parameter checks
17
D7F 710
engine -
35 tracks
Carry out the actions below if the engine does not start.
Otherwise, refer to the following pages.NOTES
3
17-105
Page 159 of 363
Check the insulation and continuity of the wiring:
Fuel pump relay 5 Impact sensor
Impact sensor C1 Fuel pump
Repair if necessary.
Check the 25A fuel pump fuse.
Check the insulation and continuity of the wiring:
Fuel pump fuse 3 Fuel pump relay
Repair if necessary.
JSA051.0
INJECTION
Fault finding - Status and parameter interpretation17
D7F 710
engine -
35 tracks
AFTER REPAIRStart the status and parameter check again from the beginning.
DIAG 6
Fiche n° 27
FUEL PUMP
XR25 aid:The command mode should cause the fuel pump to operate
No fault bargraphs should be illuminated.NOTES
Check the hygiene and presence of earth on track C2 of the fuel pump.
If + 12 V is not reaching the fuel pump, replace the fuel pump relay.
If + 12 V is reaching the fuel pump, replace the fuel pump.
17-114
Page 167 of 363
JSA051.0
INJECTION
Fault finding - Status and parameter interpretation17
D7F 710
engine -
35 tracks
AFTER REPAIRStart the status and parameter check again from the beginning.
DIAG 14
Fiche n° 27 side 2/2
ADAPTIVE RICHNESS
XR25 aid:Minimum < # 30 < Maximum
Minimum < # 31 < Maximum
No fault bargraphs should be illuminated.
Carry out the programming operations.NOTES
Ensure the canister bleed valve is sealed.
Erase the computer memory.
Engine warm , running at idle speed, check the values for # 30 and # 31.
-If # 30 or # 31 is at a MAXIMUM, there is not enough fuel.
-If # 30 or # 31 is at a MINIMUM, there is too much fuel.
Ensure the hygiene, cleanliness and correct operation of :
- filter
- fuel pump
- fuel circuit
- fuel tank.
17-122
Page 185 of 363
JSA051.0
INJECTION
Fault finding - Checking conformity
17
D7F 710
engine -
35 tracks
Engine warm, at idle speed, after fan assembly has operated at least once NOTES
Order of
operationsFunction to be
checkedAction Bargraph Display and notes
4
(cont)Interpretation of
normally illuminated
bargraphs (cont)
-
Fuel pump active
Illuminates after erasing the
memory to indicate that the
operation has been carried out
correctly
Computer configured for:
manual gearbox (G50*2*)
automatic transmission
(G50*1*)
5 Idle speed# 06
# 12X = 740 ± 50 rpm
4 % < X < 14 %
6Anti-pinking noise
measurement# 13
(3500 rpm, no
load) X variable and not zero
7
19
12
19
6
17-140
Page 198 of 363

Connect the bornier in place of the computer and check the insulation and continuity of the line:
Computer 18 Earth
Computer 2 Earth
Computer 3 Earth
Computer 11 7 Diagnostic socket
Computer 38 15 Diagnostic socket
Computer 1 5 Main relay
Computer 40 2 Main relay
Computer 48 2 Fuel pump relay
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 1 RH 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.
Check, ignition on, for 12 V on track:
- 1 on the main relay,
- 3 on the main relay,
- 1 on the fuel pump relay.
Repair if necessary.
Ignition on, check for 12 V on track 5 of the main relay:
- If there is 12 V on track 5 of the main relay: replace the fuel pump relay.
- If there is not 12 V on track 5 of the main relay: replace the main relay.
17-155
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.
17-159
Page 209 of 363
Check the insulation from 12 V of line :
Computer 48 2 Fuel pump relay
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 8 LH side illuminated Fiche n° 27 side 1/2
FUEL PUMP CIRCUIT
XR25 aid:Only detection of CC+ on line 48 of the computer
8
CO or CC- on line 48 of the computer prevents dialogue with 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.
The fault persists! Replace the fuel pump relay.
17-166
Page 210 of 363

Connect the bornier in place of the computer and check the insulation and continuity of the line :
Computer 30 2 Injectors 1 and 4
Computer 4 2 Injectors 2 and 3
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 11 LH side illuminated Fiche n° 27 side 1/2
INJECTOR CIRCUIT
XR25 aid:*11 = XX.CO=> CO or CC- line 30 or 4 of the computer
*11 = XX.CC=> CC+ line 30 or 4 of the computer
11
XX = 14 => Cylinder 1 or 4 line 30 of the computer
XX = 23 =
> Cylinder 2 or 3 line 4 of the computerNOTES
Check the resistance of the value for the two faulty injectors.
Replace the injector/s if necessary.
When the ignition is switched on and during the timed phase, check for 12 V on track 1 of the faulty
injector.
If necessary, repair the line from track 1 injector to track 5 fuel pump relay.
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.
17-167