Check the Key Sensor In the Ignition Switch

Check the key sensor in the ignition switch

Checking the key sensor signal




- Ignition off.
Check the voltage in the central electronic module (CEM) connector, terminal #B1 (#A21). The voltage must be battery voltage.
Remove the key from the ignition switch. The voltage must now be approximately 0 V.

Other information
- To access or replace the central electronic module (CEM) connector, see Central electronic module (CEM), replacing Central Electronic Module (CEM), Replacing
- To connect the breakout box to the control module, see Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- For further information about signals and other values, see Signal specification Pinout Values and Diagnostic Parameters









Is the voltage OK?

Yes - No Fault Found

No - Checking the ignition switch

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Checking the ignition switch




- Ignition off
- Key out
- Disconnect the connector for the ignition switch.
Check the voltage in the central electronic module (CEM) connector, terminal #B1 (#A21).

Other information
- To access the ignition switch, see Steering wheel lock, replacing Service and Repair









Does the voltage drop to approximately 0V?

Yes - Replacing the ignition switch

No - Checking the wiring

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Checking the wiring




- Ignition off
- Key out.
Check the cable between central electronic module (CEM) connector terminal #B1 (#A21) and ignition switch connector terminal #3 (#S). Check for a short-circuit to battery voltage.

Other information
- To access the ignition switch, see Steering wheel lock, replacing Service and Repair









Was a fault detected?

Yes - Verification

No - No Fault Found

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Replacing the ignition switch




- Ignition off
- Key out.
Replace the ignition switch. See Steering wheel lock, replacing Service and Repair.





Continue - Verification

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Verification

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








- Ignition off
- Reinstall the connectors, components etc.
Open the driver's door.
Check to see if the key warning signal functions normally and silences when the key is removed from the ignition switch

Was the function OK?

Yes - Fault Found

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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - No Fault Found

Attempt New Test - Checking the key sensor signal

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