Page 110 of 363
JF5111.0
INJECTION
Fault finding -Aid
17
E7J 780
engine
For further details, refer to section 12
Injector resistance = 14.5 Ω
Idle regulation stepping
motor resistance : A - D = 52 Ω
B - C = 52 Ω
Canister bleed valve resistance = 35 Ω
Ignition coil resistance : Primary = 1-3 ; 2-3 = 1 Ω
1-2 = 0.5 Ω
Secondary = 10 kΩ
Oxygen sensor heating resistance = 3 to 15 Ω
Throttle potentiometer resistance : no load 1-2 = 5440 Ωfull load 1-2 = 2200 Ω
1-3 = 4500 Ω1-3 = 4460 Ω
2-3 = 2160 Ω2-3 = 5340 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 ohms7470
to
119703060
to
40451315
to
1600--
Coolant temperature sensor
Resistance in ohms6700
to
80002600
to
30001100
to
1300270
to
300200
to
215
17-62
Page 111 of 363
JF5111.0
INJECTION
Fault finding - Checking conformity
17
E7J 780
engine
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
17-63
Page 112 of 363
JF5111.0
INJECTION
Fault finding - Checking conformity
17
E7J 780
engine
Engine cold, ignition on.NOTES
Order of
operationsFunction to be
checkedAction Bargraph Display and notes
5 Interpretation of
normally illuminated
bargraphs
Code present
No load recognition
Illuminated if immobiliser
active
+ after ignition information
received
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*)
1
2
3
4
12
19
19
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Page 113 of 363
JF5111.0
INJECTION
Fault finding - Checking conformity
17
E7J 780
engine
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 16 < X < 50
185 < X < 243
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
10Idle speed regulation
stepping motor# 12The value read is variable
depending on the coolant
temperature :
7 % ≤ X ≤ 100 %
11Engine speed
# 06 X = 0 rpm
12Canister bleed
# 23 X = 0.7 %
2
2
2
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Page 115 of 363
JF5111.0
INJECTION
Fault finding - Checking conformity
17
E7J 780
engine
Engine warm, at idle speed, after fan assembly has operated at least once (air
conditioning not selected).NOTES
Order of
operationsFunction to be
checkedAction Bargraph Display and notes
4 Interpretation of
normally illuminated
bargraphs
-
Code present
No load recognition
Engine speed information
received
+ after ignition information
received
Idle speed regulation active
Richness regulation active
Fuel pump active1
2
4
6
6
3
7
17-67
Page 120 of 363
JSA051.0
INJECTION
Fault finding- Introduction
17
D7F 710
engine -
35 tracks
SETTING UP DIALOGUE BETWEEN THE XR25 AND THE COMPUTER
- Connect the test kit to the diagnostic socket.
- Put the selector on S8
- Switch on the ignition.
- Enter D13 9.NJ
COMPUTER IDENTIFICATION
The computer is not identified by reading a fault code but by reading the Part Number directly from the
computer. After having set up a dialogue with the computer:
ENTER G70*7700
XXX
XXX
The Part Number will then appear on the central display in three sequences.
Each sequence is displayed for approximately two seconds. The display is repeated twice .
ERASING THE MEMORY (ignition on)
After an operation on the injection system the computer’s memory can be erased by using the code G0** .
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Page 122 of 363

JSA051.0
INJECTION
Fault finding - Introduction
17
D7F 710
engine -
35 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 123 of 363

JSA051.0
INJECTION
Fault finding - Introduction
17
D7F 710
engine -
35 tracks
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.
17-78