Page 154 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 1
Fiche n° 27
BATTERY VOLTAGE
XR25 aid:Battery voltage, ignition on, Minimum < # 04 < Maximum
Battery voltage, idle speed, Minimum < # 04 < Maximum
No fault bargraphs should be illuminated.
No consumersNOTES
If # 04 < Minimum, the battery is discharged:
Check the charging circuit to determine the cause of this fault.
Ignition on
If # 04 > Maximum, the battery may be overcharged:
Check the charging voltage is correct with and without consumers.
If # 04 < Minimum, the charging voltage is too low:
Check the charging circuit to determine the cause of this fault.
At idle speed
If # 04 > Maximum, the charging voltage is too high:
The alternator regulator is faulty. Repair this fault and check the electrolyte level in the battery.
NOTE:
The battery and the charging circuit may be checked using the OPTIMA 5800 station (measurement does
not require the battery to be disconnected, which retains the memories of the computers).
17-109
Page 155 of 363

Check the insulation and continuity of the line:
Computer 3 C Throttle potentiometer
Computer 5 B Throttle potentiometer
Computer 15 A Throttle potentiometer
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 2
THROTTLE POTENTIOMETERFiche n° 27
XR25 aid:# 17 outside tolerances
# 17 does not vary when throttle moves
Status BG 2LH or 2RH, incorrect illumination
No fault bargraphs should be illuminated.
Ignition on or engine running.NOTES
Status bargraph 2RH
incorrect illuminationNoneNOTES
Check the resistance of the throttle potentiometer.
Replace the throttle potentiometer if necessary.
# 17 is fixedNoneNOTES
Check the resistance of the throttle potentiometer when the throttle butterfly is moved.
If the resistance varies, check the electrical lines of the sensor.
If the resistance does not vary, check that the sensor is connected mechanically to the throttle.
If necessary, replace the sensor.
# 17 outside tolerancesNoneNOTES
Check the upper and lower stops of the throttle butterfly.
Check the accelerator control (points of resistance and friction).
Repair.
17-110
Page 162 of 363

Check the insulation, continuity and that there is no interference resistance
on the line:
Computer 5 C Pressure sensor
Computer 15 A Pressure sensor
Computer 23 B Pressure sensor
Repair if necessary.
JSA052.0
INJECTION
Fault finding - Status and parameter interpretation17
D7F 710
engine -
35 tracks
AFTER REPAIRStart the status and parameter check again from the beginning.
DIAG 9
Fiche n° 27
PRESSURE CIRCUIT
XR25 aid:Ignition on # 01 not coherent
At idle speed # 01 < Minimum or # 01 > Maximum
# 16 not coherent
No fault bargraphs should be illuminated.NOTES
# 01 not coherent
ignition on
# 01 < Minimum at idle
speed
# 16 not coherent
If all these points are correct, replace the sensor.
A vacuum pump with a pressure gauge may be used to check coherence with
# 01 and to show a faulty sensor.
# 01 > Maximum at idle
speedThe manifold pressure is often a sign of incorrect engine operation. Check
- the sealing of the pipe between the manifold and the sensor,
- the valve clearances,
- the canister bleed valve which should be closed at idle speed,
- cylinder compression using the OPTIMA 5800 station.
If all these points are correct, replace the sensor.
A vacuum pump with a pressure gauge may be used to check coherence with
# 01 and to show a faulty sensor.
17-117
Page 163 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 10
Fiche n° 27
RICHNESS REGULATION
XR25 aid:Richness regulation faulty
No fault bargraphs should be illuminated.
Ignition correct (a check may be made using the OPTIMA 5800 station).
No other status bargraph should show a fault.
NOTES
Check the sealing of the canister bleed valve (a leak can disrupt the richness considerably).
Check the sealing of the exhaust pipe upstream from the oxygen sensor.
Check the sealing of the inlet manifold.
If the vehicle has only been driven in town, the sensor is contaminated (try driving under load).
Check the fuel pressure.
If the idle speed is unstable, check the valve clearances.
Check the injectors (flow and shape of the jet).
If necessary, replace the oxygen sensor.
17-118
Page 169 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 15
CONT
Fiche n° 27
No fault bargraphs should be illuminated.NOTES
NOTES λ > 1.03
at 2500 rpmNone
The oxygen sensor loops correctly at 2500 rpm.
NOTES λ < 0.97
at 2500 rpm.The oxygen sensor does not loop correctly at 2500 rpm., CO >
0.3 % at 2500 rpm.
Check the pressure sensor.
Check the sensor.
Check that an injector is not faulty.
Check there is no leak at the exhaust.
Check that an injector has not seized.
Check the fuel pressure is not too low.
The oxygen sensor does not loop correctly at 2500 rpm.
Check there is not an injection fault.
Check there is not an ignition fault.
Check the sensor is not faulty.
Check the fuel pressure.
17-124
Page 170 of 363

Check the insulation and continuity of the line:
Relay 5 1 Fan assembly
Fan assembly 2 Earth
Repair.
Connect the bornier in place of the computer and
check the insulation and continuity of the line:
Bornier 27 2 Relay
Repair.
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 16
Fiche n° 27
ANTIPERCOLATION RELAY
XR25 aid:The fan assembly must operate when command mode G17* is used.
No fault bargraphs should be illuminated.NOTES
The antipercolation relay
does not click when its
command mode is used
There is 12 V
on track 1
Ignition on, check for 12 V on track 1 of the fan assembly relay.
There is not 12 V
on track 1Check the line for track 1 of the relay to the fuse.
The antipercolation relay
does click when its
command mode is usedFan assembly relay in place, check, during operation of the command mode,
for 12 V on track 5 of the fan assembly relay.
There is not 12 V
on track 5Check the insulation and continuity of line 3 on the
relay to the fuse.
Repair if necessary.
The fault persists, replace the fan assembly relay.
There is 12 V
on track 5
If the fan assembly still does not operate, replace the
fan assembly.
The fault persists, replace the relay.
The fault persists!
Replace the injection computer.
17-125
Page 179 of 363
JSA051.0
INJECTION
Fault finding -Aid
17
D7F 710
engine -
35 tracks
For further details, refer to section 12
Injector resistance = 14.5 Ω
Idle regulation stepping
motor resistance : A - D= 100 Ω
B - C = 100 Ω
Canister bleed valve resistance = 35 Ω
Ignition coil resistance : Primary = 1-4 ; 1-3 ; 2-3 ; 2-4 = 1.5 Ω
3-4 = 0.6 Ω
Secondary = 8 kΩ
Oxygen sensor heating resistance = 3 to 15 Ω
Throttle potentiometer resistance : no load A-B = 1300 Ωfull load A-B = 1300 Ω
A-C = 1360 ΩA-C= 2350 Ω
B-C = 2300 ΩB-C = 1260 Ω
Flywheel signal resistance = 220 Ω
Fuel pressure = 3 bars ignition on/ 2.5 bars at idle speed
Value for: CO = 0.3 % maximum
HC = 100 ppm maximum
CO2 = 14.5 % minimum
Lambda = 0.97 < λ < 1.03
Sensor resistance
Temperature in °C 0 20 40 80 90
Air temperature sensor
Resistance in ohms5000
to
70001700
to
3300500
to
1550--
Coolant temperature sensor
Resistance in ohms6700
to
80002600
to
30001100
to
1300270
to
300200
to
215
17-134
Page 180 of 363
JSA051.0
INJECTION
Fault finding - Checking conformity
17
D7F 710
engine -
35 tracks
Engine cold, ignition on.NOTES
Order of
operationsFunction to be
checkedAction Bargraph Display and notes
1 Dialogue with XR25D13
(selector on
S8)
9.NJ
Use fiche n° 27
fault test side
2Interpretation of
normally illuminated
bargraphsFault test
Code present
3 ImmobiliserIf the vehicle does not have an
immobiliser, this bargraph
should be illuminated.
4 Change to status testG01*
10.NJ
Use fiche n° 27
status test side
1
1
2
17-135