Page 124 of 363
JSA051.0
INJECTION
Fault finding - Introduction
17
D7F 710
engine -
35 tracks
Driving conditions for programming the adaptive variables:
During the road test, the engine speed must be stabilised for a few moments between:
260 < # 01 < 385 mbars
then 385 < # 01 < 510 mbars
then 510 < # 01 < 635 mbars
then is 635 < # 01 < 760 mbars
then 760 < # 01 < 970 mbars
Do not exceed an engine speed of 4400 rpm
The engine must be warm (coolant temperature > 75 °C).
For this test, start from a fairly low engine speed, in 3rd or 4th gear, and apply progressive acceleration to
stabilise at the pressure required for 10 seconds in each zone.
The test must then be continued by driving normally, in a varied manner for 3 to 6 miles (5 to 10 km).
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Page 133 of 363

Connect the bornier in place of the computer and check the insulation and continuity of the line:
Computer 15 1 Coolant temperature sensor
Computer 6 2 Coolant temperature sensor
Repair if necessary.
JSA051.0
INJECTION
Fault finding - Interpretation of XR25 bargraphs17
D7F 710
engine -
35 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 illuminatedFiche n° 27 side 1/2
COOLANT TEMPERATURE SENSOR CIRCUIT
XR25 aid:CO, CC- or CC+line 15 or 6
4
If BG 3LH or BG 5LH or BG 6LH or BG 6RH is also illuminated, check line 15 on 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.
17-88
Page 149 of 363
JSA051.0
INJECTION
Fault finding - Status and parameter checks
17
D7F 710
engine -
35 tracks
Engine cold, ignition on.NOTES
Order of
operationsFunction to be
checkedAction Bargraph Display and notes Fault finding
6Throttle
position
potentiometer
.No load
# 17
Accelerator
pedal
slightly
depressed
Full load
# 1710 < X < 50
185 < X < 245
DIAG 2
7
Pressure sensor# 01X =Atmospheric pressureDIAG 9
8Coolant
temperature
sensor# 02
X = Engine temperature
± 5 °CDIAG 3
9Air
temperature
sensor# 03
X = Temperature under
bonnet ± 5 °CDIAG 4
10 Fan assemblyG17*Fan must operateDIAG 16
11Fault warning
light Switch
ignition onFault warning light must
illuminate then
extinguishDIAG 18
2
2
2
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Page 156 of 363
Check the insulation, continuity and that there is no interference resistance on the electrical line :
Computer 6 2 Coolant temperature sensor
Computer 15 1 Coolant temperature sensor
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 3
Fiche n° 27
COOLANT TEMPERATURE
XR25 aid: # 02 = Engine temperature ± 5 °C
No fault bargraphs should be illuminated.NOTES
If the value read is incoherent, check the sensor is correctly following the standard table of values for
"resistance as a function of temperature".
Replace the sensor if the values are incorrect (
NOTE : If a sensor is incorrect, this is often due to an electric
shock).
17-111
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 182 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
6 Throttle position
potentiometerNo load
# 17
Accelerator
pedal slightly
depressed
Full load
# 17 10 < X < 50
185 < X < 245
7Absolute pressure
sensor# 01
X = Local atmospheric pressure
8Coolant temperature
sensor# 02 X = Ambient temperature
± 5 °C
9Air temperature
sensor# 03 X = Ambient temperature
± 5 °C
10
Idle speed regulation
stepping motor# 12The value read is variable
depending on the coolant
temperature :
11 % ≤ X ≤ 100 %
11Engine speed
# 06 X = 0 rpm
12
Canister bleed# 23 X = 0.7 %
2
2
2
17-137
Page 194 of 363
JSA052.0
INJECTION
Fault finding - Introduction
17
D7F 710
engine -
55 tracks
Driving conditions for programming the adaptive variables:
During the road test, the engine speed must be stabilised for a few moments between:
260 < # 01 < 385 mbars
then 385 < # 01 < 510 mbars
then 510 < # 01 < 635 mbars
then is 635 < # 01 < 760 mbars
then 760 < # 01 < 970 mbars
Do not exceed an engine speed of 4400 rpm
The engine must be warm (coolant temperature > 75 °C).
For this test, start from a fairly low engine speed, in 3rd or 4th gear, and apply progressive acceleration to
stabilise at the pressure required for 10 seconds in each zone.
The test must then be continued by driving normally, in a varied manner for 3 to 6 miles (5 to 10 km).
17-151
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.
17-160