Signal Missing or Too Low. Permanent Fault
Signal missing or too low. Permanent fault
Checking / replacing component
Remove relay (2/114) and check the relay base switches for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Install the relay.
Activate the relay.
If the function is now OK the fault was caused by a contact fault in the relay base.
Other information:
- To access the integrated relay / fusebox in the cargo compartment, see Relay/fuse box cargo compartment/Rear electronic module (REM), replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Was the function OK?
Yes - Verification
No - Replacing the component
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Replacing the component
Replace relay, 2/114.
Activate the relay.
If the function is now OK, the cause of the fault was a defective relay (short-circuit to ground or an open-circuit in the relay).
Other information:
- To access the integrated relay / fusebox in the cargo compartment, see Relay/fuse box cargo compartment/Rear electronic module (REM), replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Was the function OK?
Yes - Fault Found
No - Checking the control module for open-circuits
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Checking the control module for open-circuits
- Remove relay 2/114.
Check the driver circuit for the relay coil for an open-circuit as follows: Activate the relay driver. Measure the voltage between terminals #1 and #2 on the relay base.
For further information about open-circuits, see Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Hint: The voltage between terminals #1 and #2 should be battery voltage.
If the value deviates excessively, check the voltage between terminal #2 and the battery and between terminal #1 and ground. Both should equal battery voltage.
Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Do not forget to check that the power supply to the control module is OK.
Other information:
- To access the integrated relay / fusebox in the cargo compartment, see Relay/fuse box cargo compartment/Rear electronic module (REM), replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Was a fault detected?
Yes - Verification
No - Checking the control module for short-circuits
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Checking the control module for short-circuits
Measure the resistance between terminal #2 and ground when the relay driver is active.
The resistance should be high when the relay driver is active.
Replace the control module if the resistance is low.
Other information:
- To access the integrated relay / fusebox in the cargo compartment, see Relay/fuse box cargo compartment/Rear electronic module (REM), replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Continue - Verification
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Verification
Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Ignition on.
Activate the relay.
Was the function OK?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFIED - Fault Found
VERIFICATION FAILED - 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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Attempt New Test - Checking / replacing component
FAULT-TRACING FAILED - No Fault Found
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