Signal Too Low

Signal too low

Checking the connectors
Check the control module and roof lamp module connectors. Check for contact resistance and oxidation. Check for loose connections.

Other information:
- For further information about signals and other values, see Signal specification Signal Specification, Upper Electronic Module (UEM)
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- To access or replace the roof lamp module, see Replacing interior lighting Service and Repair
- To access the connector for the upper electronic module (UEM), see Upper electronic module (UEM) rear view / door mirror, replacing Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals.









Was a fault detected?

Yes - Verification

No - Checking for open-circuits and short-circuits

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Checking for open-circuits and short-circuits
Check the cable between the control module and the roof lamp unit. Check for a short-circuit to ground.
Remove the connector from the roof lamp module and measure between the connector and the upper electronic module (UEM) as follows.

UEM-0034 Left front reading lamp
Control module terminal #20 and roof lamp module terminal #3A.

UEM-0036 Right front reading lamp
Control module terminal #20 and roof lamp module terminal #4A.
Check the cable between the control module and the roof lamp unit. Check for an open-circuit.

UEM-0034 Left front reading lamp
Control module terminal #18 and roof lamp module terminal #3A.

UEM-0036 Right front reading lamp
Control module terminal #6 and roof lamp module terminal #4A.
Replace the cable if a fault is found.
If the cable is OK, try a new bulb in the roof lamp module.

Other information:
- For further information about signals and other values, see Signal specification Signal Specification, Upper Electronic Module (UEM)
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- To access or replace the lamp, see Replacing interior lighting Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals.










Continue - Verification

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Verification




Verification

Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off.
- Reinstall the connectors, components etc.
- Ignition on.
Check that the relevant lamp button and lamp are functioning.

Does the lamp function?

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 - FAULT-TRACING FAILED

No - Attempt New Test

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Attempt New Test - Checking the connectors

FAULT-TRACING FAILED - No Fault Found

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