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 seat belt tensioner.
Warning! Under no circumstances use an ohmmeter or other live measuring instrument to take readings on a disconnected non-deployed pyrotechnical seat belt tensioner. This could deploy the seat belt tensioner!
- Install special tool 998 8695 TEST DEVICE 998 8695 Test Device on the seat belt tensioner 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 diagnostic trouble codes (DTCs).
If the fault is in the seat belt tensioner the diagnostic trouble code (DTC) status should now have changed to intermittent. In such a case, try replacing the seat belt tensioner and then carrying out verification.
Other information:
- To access / replace the seat belt tensioner, see Replacing front seat belts Front Seat Belt.
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 seat belt tensioner 1 and ground.
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 deviates it indicates that the cable is short-circuit to supply voltage. Replace cable harness.
Also take readings between seat belt tensioner 2 and ground.
The oscilloscope should read approximately 2 V.
Remedy as necessary.
Is the value correct?
Yes - Verification
No - No Fault Found Fault-tracing information
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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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