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 switched to intermittent fault. Try replacing the seat belt tensioner and carrying out a new verification afterwards.

Other information:
- To access / replace the seat belt tensioner, see Seat belt Service and Repair.





Does the diagnostic trouble code (DTC) status change?

Yes - Verification

No - Checking the wiring

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Checking the wiring








- Ignition off.
- Remove special tool 998 8695 TEST DEVICE 998 8695 Test Device.
- Ignition on.
Connect oscilloscope between seat belt tensioner #1 and ground. The oscilloscope should now display a spiked pulse with an interval of approximately 500 ms.
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.









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
- 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 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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