Signal missing or too low. Permanent fault
Signal missing or too low. Permanent fault
Checking the component
Remove the relay (2/59). Check the relay base switches. Check for contact resistance and oxidation.
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 Integrated relay/fuse box cargo compartment/rear electronic module, replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing
- Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Was the function OK?
Yes - Verification
No - Replacing the component
-------------------------------------------------
Replacing the component
Replace the relay, 2/59.
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 coil).
Other information:
- To access the integrated relay / fusebox in the cargo compartment, see Integrated relay/fuse box cargo compartment/rear electronic module, replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Was the function OK?
Yes - Fault Found
No - Checking the wiring
-------------------------------------------------
Checking the wiring
- Remove relay RMI 21, 2/59.
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
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.
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 Integrated relay/fuse box cargo compartment/rear electronic module, replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing
- Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Was a fault detected?
Yes - Verification
No - Checking the control module for short-circuits
-------------------------------------------------
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 Integrated relay/fuse box cargo compartment/rear electronic module, replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Continue - Verification
-------------------------------------------------
Verification
Verification
Verification
Hint: After the repair it is necessary to check that the fault has been rectified.
- Ignition off.
- Connect connectors, install components, etc.
- Ignition on.
Activate relay.
If the function is now OK, this means that the fault was caused by a short circuit in the relay driver.
Does it work?
Yes - VERIFIED
No - VERIFICATION FAILED
------------------------
VERIFIED - Fault Found
VERIFICATION FAILED - Fault-tracing information
-------------------------------------------------
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
------------------------
Attempt New Test - Checking the component
FAULT-TRACING FAILED - No Fault Found
-------------------------------------------------