Signal Too High or Signal Missing

Signal too high or signal missing

Checking components and wiring




- Ignition off.
Check the antenna cable between the phone module (PHM) connector C and the carphone antenna connector in the right-hand A post. Check for a short-circuit to supply voltage.
Check the antenna cable between control module connector A and the carphone antenna connector in the right-hand A-post. Check for an open-circuit.
Check the connectors for loose connections, damaged or bent terminal pins and oxidation.
Remedy as necessary.

Other information:
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Phone Module (PHM)
- For information about signals and connectors, see Signal specification Signal Specification, Phone Module (PHM)
- To access or replace the control module, see Phone module (PHM), replacing Phone Module (PHM), Replacing
- To access and replace the carphone antenna, see Antenna carphone, replacing Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals.









Was a fault detected?

Yes - Verification

No - Checking the connectors and wiring

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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
- Switch on the carphone.
Make a call so that both the handset and the hands-free system are used. See instruction manual.
Ignition off.
Ignition on.
Read off the diagnostic trouble codes (DTCs).
Check that the relevant diagnostic trouble code (DTC) has switched status from permanent to intermittent fault.





Has the status of the diagnostic trouble code (DTC) changed?

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 components and wiring

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Checking the connectors and wiring
Raise the secondary lock on the connector in the right A-pillar.
Loosen the primary lock and remove the insulator.
Carefully remove the antenna from the headlining.
Measure the resistance between the signal line and screen ground on the connector. The resistance must be approximately 0 ohms.
Measure the resistance between screen ground and ground. The resistance must be infinite.
Carefully remove the three screws that hold the antenna's circuit board.
Carefully lift up the circuit board from the mounting point so that there is no contact between the circuit board and the casing.
Measure the resistance between the signal line and screen ground. The resistance must be infinite. If the resistance is infinite there is a short-circuit between the signal line and screen ground.
Remedy as necessary.

Other information
- Antenna carphone, replacing Service and Repair
- Connectors, repair Connectors, Repair
- Checking wiring and terminals Checking Wiring and Terminals









Was a fault detected?

Yes - Verification

No - Fault-tracing information

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