Faulty Signal

Faulty signal

Checking communication with the gear selector module (GSM)




- Ignition on
- Gear selector in position P
- Check whether communication with the gear selector module (GSM) works by reading off the winter mode selector (W) status
- Connect and disconnect the function by pressing the switch. The status should change.
The fault is permanent if the value does not change.
If the value changes, this indicates that the fault was present previously but is not active at the moment, i.e. an intermittent fault.









Continue - Checking the wiring

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Checking the wiring
Check for external sources of interference at the communication cable (LIN) between transmission control module (TCM) terminal #A7 and gear selector module (GSM) terminal #2 that can disrupt communication.
Check the communication cable (LIN) between transmission control module (TCM) terminal #A7 and gear selector module (GSM) terminal #2. Check for intermittent short-circuits. Check for an open-circuit.

Hint: The gear selector module (GSM) connector can be accessed by removing the cigarette lighter assembly / electric socket. See: Power socket 12V Service and Repair

Other information
- Connecting the breakout box, AW55-50/51SN Connecting Breakout Box, Transmission Control Module (TCM)
- Signal specification, AW55-50/51SN Signal Specification, Transmission Control Module (TCM)
- Top panel gear selector assembly, B5254T7, AW55-50/51SN Top Panel Gear Selector Assembly
- 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.
- Gear selector in position P.
- Check whether communication with the gear selector module (GSM) works by reading off the winter mode selector (W) status.
Connect and disconnect the function by pressing the switch. The status should change.





Does the status change?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - FAULT FOUND

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Fault-tracing information

Attempt New Test - Checking communication with the gear selector module (GSM)

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