Faulty Signal. Permanent Fault
Faulty signal. Permanent fault
Checking components
- Make a note of the anti-theft radio code
- Ignition off
- Disconnect the battery negative lead
- Disconnect the connector from the driver's airbag.
Warning! Under no circumstances use an ohmmeter or other live measuring instrument to take readings on a disconnected non-deployed steering wheel module. This could deploy the airbag.
- Install special tool 998 8695 TEST DEVICE 998 8695 Test Device on the air bag connector.
Caution! The special tool must be checked and faultless. If the tool is defective it will cause errors in the diagnosis and make fault-tracing harder.
- Ignition on
- Connect the battery negative lead.
- Read off the diagnostic trouble codes (DTCs).
If the fault is in the airbag, the DTC status should now have switched to intermittent fault. Try replacing the driver's airbag and carrying out a new verification afterwards.
Other information:
- To access or replace the driver's airbag, see Steering wheel module, steering wheel and contact reel, replacement Airbag Driver's Side (SRS), Replacing.
Does the status of the diagnostic trouble code (DTC) change?
Yes - Verification
No - Checking the cable and control module
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Checking the cable and control module
- Ignition off
- Remove the contact reel
- Ignition on.
Connect an oscilloscope between contact reel terminal #1 and ground. The oscilloscope should now display a spiked pulse with an interval of approximately 500 ms.
If the value is normal the fault is in the contact reel. Replace the contact reel.
If the value deviates it indicates that there is a short-circuit in the cable. Replace the cable harness.
Check the control module terminal pins visually.
Check that the plastic pins are not damaged. Their function is to separate the short-circuiting element from the terminal pins when the control module is connected.
The control module must be replaced if the plastic pins are damaged.
Remedy as necessary.
Other information:
- To access and replace contact reel, see Steering wheel module, steering wheel and contact reel, replacement Airbag Driver's Side (SRS), Replacing
- To access and replace the control module, see Sensor module, replacement Service and Repair.
Select Continue when the fault has been remedied.
Continue - Verification
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Verification
Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Disconnect the battery negative lead
- Reinstall the connectors, components etc.
- Ignition on
- Connect the battery negative lead.
Warning! There must not be anyone inside the passenger compartment when the battery is connected.
- Read off diagnostic trouble codes (DTCs).
The fault is no longer present if the status of the diagnostic trouble code (DTC) has changed to intermittent.
Does the status change?
Yes - VERIFIED
No - VERIFICATION FAILEDPAPER
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VERIFIED - FAULT FOUND
VERIFICATION FAILED - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - FAULT-TRACING FAILED
No - Attempt New Test
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FAULT-TRACING FAILED - FAULT-TRACING FAILED
Attempt New Test - Checking components
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