Signal Too High. Permanent Fault
Signal too high. Permanent fault
Checking component
- 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 airbag module. This could deploy the airbag!
- Install special tool 998 8695 TEST DEVICE 998 8695 Test Device on the driver's airbag 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.
- Connect the battery negative lead.
- Ignition on.
- Read off diagnostic trouble codes (DTCs).
If the fault is in the passenger airbag, the status of the diagnostic trouble code (DTC) will have switched to an intermittent fault. Try replacing the driver airbag and then carrying out a new verification.
Other information:
- To access / replace the driver's airbag, see Airbag steering wheel module, steering wheel and contact reel replacement Airbag Steering Wheel Module, Steering Wheel and Contact Reel Replacement.
Does the diagnostic trouble code (DTC) status change?
Yes - Verification
No - Checking components and wiring
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Checking components and wiring
- Ignition off.
- Remove special tool 998 8695 TEST DEVICE 998 8695 Test Device.
- Ignition on.
Connect an oscilloscope between driver's airbag 1 and 2. The oscilloscope should indicate a spiked pulse with a cyclic time of approximately 500 ms and an offset off approximately 2 V.
If the value is not correct, there is a short-circuit to battery voltage in the cable or in the contact reel.
Also take a reading between ground and airbag 2. The oscilloscope should display approximately 2 V.
Note! Diagnostic trouble code (DTC) SRS-212 is stored after this reading. Ignore this DTC, this is because the driver's airbag is disconnected.
Continue - Checking the wiring
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Checking the wiring
- Ignition off.
- Airbag disconnected.
- Disconnect the control module.
- Ignition on.
Connect a voltmeter between the contact reel connector and ground.
The voltmeter should read 0 V.
If value is not correct the contact reel must be replaced.
If the value is correct the fault is in the cable. In this case the cable harness must be replaced.
Remedy as necessary.
Other information:
- To access / replace the contact reel, see Airbag steering wheel module, steering wheel and contact reel replacement Airbag Steering Wheel Module, Steering Wheel and Contact Reel Replacement.
- To access / replace the control module, see Replacing the SRS module Service and Repair.
Select Continue when the fault has been remedied.
Continue - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Reinstall the connectors, components etc.
- Ignition on.
- Read off diagnostic trouble codes (DTCs).
If the DTC status changed to intermittent it means that the fault is no longer present.
Does the status change?
Yes - VERIFIED
No - VERIFICATION FAILED
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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 - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking component
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