Fault-Tracing Information

Fault-tracing

Checking the battery voltage




- Ignition on.
- Read off the voltage for the transmission control module (TCM) and the central electronic module (CEM).
The voltage supply for the transmission control module (TCM) and central electronic module (CEM) must be approximately the same.
If the voltage supply to the transmission control module (TCM) differs by more than 2.0 V from that of the central electronic module (CEM), a permanent fault is indicated.
If the voltage is approximately the same, this indicates an intermittent fault, i.e. the fault was present previously but is not active at the moment.





Continue - Checking the power supply

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Checking the power supply




- Ignition off.
Check the connector of the transmission control module (TCM) for contact resistance and oxidation.
Check the power supply cable between the transmission control module (TCM) fuse in the engine compartment relay/fuse box and connection #A1 (#31) for short circuit to ground.

Hint: With the ignition on and the voltmeter connected between terminals #A1 (#31) and #A9 (#A39) on the breakout box, the voltmeter should read battery voltage.

Other information
- Signal specification Signal Description, Transmission Control Module (TCM)
- Checking wiring and terminals Checking Wiring And Terminals









Continue - Verification

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Fault-tracing information

Attempt New Test - Checking the battery voltage

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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.
- Read the voltage supply for the transmission control module (TCM) and central electronic module (CEM).
The voltage must be approximately battery voltage.





Was the voltage OK?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - FAULT FOUND

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