82A-4V1 MR-376-X76-82A000$010.mif
ENGINE IMMOBILISER
Fault finding – Introduction82A
SVT
Vdiag No.: 04
Faults
Faults are declared present or stored (depending on whether they appeared in a certain context and have
disappeared since, or whether they remain present but are not diagnosed within the current context).
The present or stored status of faults must be considered when the diagnostic tool is used after the + after ignition
feed is switched on (without operating the system components).
For a present fault, apply the procedure described in the Interpretation of faults section.
For a stored fault, note the faults displayed and apply the Notes section.
If the fault is confirmed when the instructions in the Notes section are applied, the fault is present. Deal with the
fault.
If the fault is not confirmed, check:
– the electrical lines which correspond to the fault,
– the connectors for these lines (for oxidation, bent pins, etc.),
– the resistance of the faulty component,
– the condition of the wires (melted or split insulation, wear).
Customer complaints - Fault finding chart
If the test with the diagnostic tool is OK but the customer complaint is still present, the fault should be processed by
customer complaints.
A summary of the overall procedure to follow is provided on the following page in the form of a flow chart
82A-6V1 MR-376-X76-82A000$010.mif
ENGINE IMMOBILISER
Fault finding – Introduction82A
SVT
Vdiag No.: 04
5. FAULT FINDING PROCEDURE (continued)
Wiring check
Fault finding problems
Disconnecting the connectors and/or manipulating the wiring may temporarily remove the cause of a fault.
Electrical measurements of voltage, resistance and insulation are generally correct, especially if the fault is not
present when the analysis is made (stored fault).
Visual inspection
Look for damage under the bonnet and in the passenger compartment.
Carefully check the fuses, insulators and wiring harness routing.
Look for signs of oxidation.
Physical inspection
While manipulating the wiring, use the diagnostic tool to note any change in fault status from stored to present.
Make sure that the connectors are properly locked.
Apply light pressure to the connectors.
Twist the wiring harness.
If there is a change in status, try to locate the source of the fault.
Inspection of each component
Disconnect the connectors and check the appearance of the clips and tabs, as well as the crimping (no crimping on
the insulating section).
Make sure that the clips and tabs are properly locked in the sockets.
Check that no clips or tabs have been dislodged during connection.
Check the clip contact pressure using an appropriate model of tab.
Resistance check
Check the continuity of entire lines, then section by section.
Look for a short circuit to earth, to + 12 V or with another wire.
If a fault is detected, repair or replace the wiring harness.
