Faulty Signal

Faulty signal

Erasing diagnostic trouble codes (DTCs)




- Ignition on.




- Erase DTCs.

Continue - Reading off diagnostic trouble codes (DTCs).

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Reading off diagnostic trouble codes (DTCs).




- Remove key from ignition switch
- Ensure that all doors, the hood and trunk lid are shut.
- Lock the car with the remote control.
- Wait approximately 10 seconds.
- Unlock the car with the remote control.
- Ignition on.




- Read off diagnostic trouble codes (DTCs).

Does diagnostic trouble code (DTC) GLA-421 recur?

Yes - Checking connectors

No - Intermittent fault

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Checking connectors




- Ignition off.
- Expose VGLA control module according to Replacing main control module Replacing Main Control Module.
- Remove glove compartment according to Panel and SRS passenger airbag module Panel and SRS Passenger Airbag Module.
Check glass breakage sensor and VGLA control module connectors for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Ignition on.




- Erase DTCs.

Continue - Reading off diagnostic trouble codes (DTCs).

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Reading off diagnostic trouble codes (DTCs).




- Remove key from ignition switch
- Ensure that all doors, the hood and trunk lid are shut.
- Lock the car with the remote control.
- Wait approximately 10 seconds.
- Unlock the car with the remote control.
- Ignition on.




- Read off diagnostic trouble codes (DTCs).

Does diagnostic trouble code (DTC) GLA-421 recur?

Yes - Checking cables

No - FAULT FOUND

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Checking cables




- Ignition off.
Check fuse 13.

Hint: If the fuse is blown, check the circuit after fuse 6 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Check cable between control module #A22 and glass breakage sensor #4 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault , short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check cable between fuse 13 and glass breakage sensor connector #1 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check cable between glass breakage sensor #5 and ground for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Other information:
- The voltage between glass breakage sensor connector #1 and ground should be battery voltage.
Remedy as necessary.









Were any faults found in the cables?

Yes - Erasing diagnostic trouble codes (DTCs)

No - Replacing component

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Replacing component
Try a new glass breakage sensor according to Replacing glass breakage sensor Removal and Replacement.

Continue - Erasing diagnostic trouble codes (DTCs)

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Erasing diagnostic trouble codes (DTCs)




- Ignition on.
Erase DTCs.






Continue - Verification

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Verification

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




- Ignition off.
- Reinstall connectors, components etc.
- Remove the key.
- Ensure that all doors, the hood and trunk lid are shut.
- Lock the car with the remote control.
- Wait approximately 10 seconds.
- Unlock the car with the remote control.
- Ignition on.




- Read off diagnostic trouble codes (DTCs).

Does diagnostic trouble code (DTC) GLA-421 recur?

Yes - Fault-tracing information

No - FAULT FOUND

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Fault-tracing information
Verification indicates that the fault persists.

Do you want to repeat fault-tracing?

Yes - Erasing diagnostic trouble codes (DTCs)

No - No Fault Found

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Intermittent fault
Check cable between control module #A22 and glass breakage sensor connectors #4 for an intermittent short-circuit to ground according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults and an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults. Check cable between fuse 13 and glass breakage sensor connector #1 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults. Check cable between glass breakage sensor #5 and ground for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.










Continue - Fault-tracing information

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Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.

Do you want to repeat fault-tracing?

Yes - Erasing diagnostic trouble codes (DTCs)

No - No Fault Found

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