Signal Too Low

Signal too low

Checking the component and wiring




- Ignition off
- Light switch in position 0
- Disconnect connector A to the left-hand gas discharge lamp module (GDL).
Check the connectors for contact resistance and oxidation. Check for damage carefully.
Check the signal cable between the central electronic module (CEM) and the left-hand gas discharge lamp module (GDL). Check for an open-circuit. Check for a short-circuit to ground.
Take readings between:
- Central electronic module (CEM) terminal #E29 (#29) and left-hand gas discharge lamp module (GDL) terminal #A6.
Check that the left-hand gas discharge lamp module (GDL) is connected to ground.
Take readings between:
- Left-hand gas discharge lamp module (GDL) terminal #A10 and ground.
Remedy as necessary.

Other information:
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM) Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- Signal specification Signal Description, Central Electronic Module (CEM)
- Location of components Component Location, Central Electronic Module (CEM)
- Control module relay box passenger compartment Service and Repair
- Headlamp ballast (Xenon) Headlamp Ballast (Xenon)
- Checking wiring and terminals Checking Wiring and Terminals





Was a fault detected?

Yes - Verification

No - Checking the voltage

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Checking the voltage




- Ignition off
- Connect the breakout box adapter for the central electronic module (CEM)
- Ignition on
- Light switch in position 2.
Check the supply voltage to the gas discharge lamp module (GDL).
Take readings between:
- Central electronic module (CEM) terminal #E29 (#29) and ground.

Hint: This output powers both the left-hand and the right-hand gas discharge lamp modules (GDL).

The supply voltage to the gas discharge lamp module (GDL) must be approximately 12 V and must not be less than 8 V.
Remedy as necessary.

Other information:
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- Signal specification Signal Description, Central Electronic Module (CEM)
- Location of components Component Location, Central Electronic Module (CEM)
- Control module relay box passenger compartment Service and Repair
- Headlamp ballast (Xenon) Headlamp Ballast (Xenon)
- Checking wiring and terminals Checking Wiring and Terminals

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
- Light switch in position 2.
Switch between high and low beam.
Check that the function is OK.

Is the function OK?

Yes - Troubleshooting procedure complete

No - 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 the component and wiring

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