No Signal. Permanent Fault
No signal. Permanent fault
Checking the components
- Make a note of any radio code.
- Ignition off.
- Disconnect the battery negative lead.
- Disconnect connector from passenger air bag.
Warning! Never use an ohmmeter or any other charged measuring instrument on a disconnected, undeployed air bag module. There is a risk that the air bag could be deployed!
- Connect the special tool 919 4732 Test dummy 919 4732 Test Dummy to the passenger air bag connector.
Caution! The special tool must be checked and fault-free. If the tool is faulty, this will cause an incorrect display in the diagnosis and make fault localization harder.
- Ignition on.
- Connect the battery negative lead.
- Read the diagnostic trouble codes.
If a fault is found in the passenger air bag the status will now have changed to intermittent fault; test by replacing the passenger air bag and verify afterwards.
Additional information:
- To access/replace passenger air bag, see Removal and Replacement.
Has the status of the diagnostic trouble code changed?
Yes - Verification
No - Checking the components and wires
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Checking the components and wires
- Ignition off.
- Disconnect the special tool 919 4732 Test dummy 919 4732 Test Dummy.
- Disconnect the battery negative lead.
- Disconnect the control unit.
Warning! Never use an ohmmeter or any other charged measuring instrument on a disconnected, undeployed air bag module. There is a risk that the air bag could be deployed!
Check the control unit connector for contact resistance and oxidation, as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault
Check in particular for damage etc.
Connect an ohmmeter between passenger air bag #1 and #2 and check for an open circuit, as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Do the necessary corrective action.
Additional information:
- To access control unit connector, see Service and Repair.
- A short circuit plate in the control unit connector ensures that contact is made between the positive lead and negative lead when the control unit is disconnected. Otherwise the air bag module may be unintentionally deployed.
Select Continue when the fault has been rectified.
Continue - Verification
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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 - Trouble-shooting information
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Trouble-shooting 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 the components
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