Page 40 of 363
DPCF01 1.0
LUCAS DIESEL INJECTION
Fault finding - Checking conformity
13
Engine warm at idle speed after at least one operation of the engine cooling fan
assembly (air conditioning not selected).NOTES
Order of
operationsFunction to check Action Bargraph Display and notes
5 EGR solenoid valve After starting
phase for
40 seconds
#24
After
40 seconds
#24EGR solenoid valve fed
X = 82
X = 0
6Computer
configuration
With AC
Without ACG50*3*
G50*8*
G50*4*
G50*9*With AC
With PAS with pump
Without AC
With conventional PAS
3
3
18
18
19
19
13-36
Page 41 of 363
DPCF01 1.0
LUCAS DIESEL INJECTION
Fault finding - Customer complaints
13
Only consult these customer complaints after a complete check using the XR25.NOTES
No dialogue from the computer to the XR25.
Idle speed too high (when air conditioning not requested)
No fast idle when air conditioning requested
Starting fault (engine will not start or is difficult to start).
Warning light illuminates with no fault shown by the XR25.
Vehicle produces black smoke at altitude
Chart 1
Chart 2
Chart 3
Chart 4
Chart 5
Chart 6
13-37
Page 42 of 363

DPCF01 1.0
LUCAS DIESEL INJECTION
Fault finding - Fault charts
13
AFTER REPAIR
Use bornier Elé. 1332 for any operations on the computer connector.NOTES
Chart 1NO DIALOGUE FROM THE COMPUTER TO THE XR25.
Ensure that the XR25 is not the cause of the fault by trying to communicate with the computer on ano-
ther vehicle. If the XR25 is not the cause of the fault and dialogue is not established with another compu-
ter on the same vehicle, a faulty computer may be causing interference on the K and L fault finding lines.
Disconnect connections successively to determine which computer is at fault.
Check the ISO selector is on position S8, that you are using the latest XR25 cassette and the correct access
code (D34).
Check the battery voltage and carry out any necessary operations to ensure the correct voltage (U battery
> 10.5 volts).
Carry out a road test then check using the XR25.
Deal with any illuminated fault bargraphs.
Check the 15 Amp fuses on the engine connection unit have not blown (positions 3 and 4).
Check the connection and condition of the connections on the computer connector and the connection
R67 engine / dashboard.
Check the computer is correctly fed:
- Earth on track 2 of the computer connector (check the condition and tightness of the engine earth
strap and the engine earth on the gearbox housing).
- + after ignition feed on track 1 of the computer connector.
Check the diagnostic socket is correctly fed:
- Earth on track 5.
- + before ignition feed on track 16.
Check and ensure the continuity and insulation of the lines in the connection diagnostic socket/
computer:
- Between track 10 of the computer connector and track 15 of the diagnostic socket.
- Between track 13 of the computer connector and track 7 of the diagnostic socket.
If fault finding is not established after these operations, replace the computer (consult the "Aid" section
for this operation).
13-38
Page 45 of 363
DPCF01 1.0
LUCAS DIESEL INJECTION
Fault finding - Fault charts
13
Carry out a road test then check using the XR25.AFTER REPAIR
If the fault persists, check the fuel supply circuits (for the pump and the injectors).
If necessary, carry out a complete check of the engine (starter drive speed, pump timing, condition of
injectors, rocker arm clearances, compression, .....).NOTES
Chart 4STARTING FAULT (ENGINE WILL NOT START OR IS DIFFICULT TO
START) (warning light extinguished).
Only consult this customer complaint after a complete check using the XR25.
If no fault is shown by the XR25, ensure that the fault is not caused by a faulty immobiliser system.
Check the operation of the preheating system:
Start command mode G10*1* and check for a voltage at the plugs.
If the plugs are not fed, check the connection of the 3 track connector on the relay unit and the condition
of the 70 Amp fuse on the engine connection unit.
13-41
Page 47 of 363
DPCF01 1.0
LUCAS DIESEL INJECTION
Fault finding - Fault charts
13
Carry out a road test then check using the XR25.AFTER REPAIR
NOTES
Chart 6VEHICLE PRODUCES BLACK SMOKE AT ALTITUDE
Only consult this customer complaint after a complete check using the XR25.
Measure the resistance of the altimetric corrector at the 10 track pump connector (between tracks 1 and
6).
Replace the altimetric corrector if the resistance is not approximately 15 ohms.
Ensure the continuity of the connection between track 1 on the pump connector, wiring side, and track 5
on the altimetric connector control relay (position H on the relay plate in the engine connection unit).
Ensure the presence of earth on track 6 of the pump connector, wiring side.
13-43
Page 48 of 363

E7J 780 ENGINE
MULTIPOINT INJECTION
FAULT FINDING
CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01
XR25 fiche . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 06
Interpretation of XR25 bargraphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 09
Status and parameter checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Status and parameter interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Customer complaints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Fault charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Aid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Checking conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Page
Page 50 of 363
JF5111.0
INJECTION
Fault finding - Introduction
17
E7J 780
engine
If the information obtained by the XR25 requires electrical continuities to be checked, connect bornier Sus.
1228.
Bornier Sus. 1228 is a 55 track base with a printed circuit on which are 55 copper coated surfaces, numbered
from 1 to 55.
Using the wiring diagrams, the tracks connecting the components to be tested can be easily identified.
IMPORTANT :
• All tests using bornier Sus. 1228 must be carried out with the battery disconnected.
• The bornier is only designed to operate with an ohmmeter. Under no circumstances should 12 Volts be
applied to the test points.
97434S
17-2
Page 51 of 363

JF5111.0
INJECTION
Fault finding - Introduction
17
E7J 780
engine
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.
17-3