88C-6V1 MR-376-X76-88C000$010.mif
AIRBAGS AND PRETENSIONERS
Fault finding – Introduction88C
2nd generation
(AC4 phase II)
5. FAULT FINDING PROCEDURE (continued)
5.1 Wiring check
Fault finding problems
Disconnecting the connectors and/or manipulating the wiring may temporarily clear the cause of a fault.
Visual inspection
Look for damage under the bonnet and in the passenger compartment.
Carefully check the protectors, insulation, and routing of the wiring, as well as the mountings.
Physical inspection
When manipulating the wiring, either use the diagnostic tool to detect a change in status, from "stored" to
"present", or the multimeter to view the status changes.
Make sure that the connectors are firmly secured.
Apply light pressure to the connectors.
Twist the wiring harness.
Checking earth insulation
This check is carried out by measuring the voltage (multimeter in voltmeter mode) between the suspect connection
and the 12 V or 5V. The correct measured value is 0V.
Checking insulation against + 12 V or + 5 V
This check is carried out by measuring the voltage (multimeter in voltmeter mode) between the suspect connection
and the earth. In the first instance, the earth may be taken on the chassis. The correct measured value is 0V.
Continuity check
A continuity check is carried out by measuring the resistance (multimeter in ohmmeter mode), with the connectors
disconnected at both ends. The expected result is in the range: 0 < X < 2 for each connection. The line must be
fully checked, and the intermediate connections are only included in the method if this saves time during the fault
finding procedure. The continuity check on the multiplex lines must be carried out on both wires. The measured
value should be between: 0 < X < 2 .
Power supply check
This check can be carried out using a test light (21 W or 5 W depending on the maximum permissible load).
