Signal Missing/Too Low. Permanent Fault
Signal missing/too low. Permanent fault
Checking the components
Remove the relay (2/67) and check the relay socket contacts for contact resistance and oxidation as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Install the relay.
Activate relay.
If the function is now OK, this means that the fault was caused by a faulty contact in the relay socket.
Additional information:
- To access the relay/fuse box in the boot, see Integrated relay/fusebox cargo compartment/Rear electronic module (REM), replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Does it work?
Yes - Verification
No - Replacing the component
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Replacing the component
Replace relay, 2/67.
Activate relay.
If the function is now OK, this means that the fault was caused by a faulty relay (open circuit/short circuit to ground in the relay coil).
Additional information:
- To access the relay/fuse box in the boot, see Integrated relay/fusebox cargo compartment/Rear electronic module (REM), replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Does it work?
Yes - FAULT FOUND
No - Checking the control unit for open circuit
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Checking the control unit for open circuit
- Remove the relay, 2/67.
Check relay coil driver for an open circuit as follows: activate the relay driver and check the voltage between points 1 and 2 in the relay socket.
For additional information regarding an open circuit, see Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Hint: The voltage between 1 and 2 must be the battery voltage.
If the value deviates from this, check the voltage between 2 and the battery voltage, and between 1 and ground, which must both be the same as the battery voltage.
Check for an open circuit as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Do not forget to check that power supply to control unit is OK.
Additional information:
- To access the relay/fuse box in the boot, see Integrated relay/fusebox cargo compartment/Rear electronic module (REM), replacing Integrated Relay/Fusebox Cargo Compartment/Rear Electronic Module (REM), Replacing.
Is there a fault?
Yes - Verification
No - Checking the control unit for a short circuit
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Checking the control unit for a short circuit
Measure the resistance between 2 and earth when the relay driver is active.
The resistance will be high when the relay driver is active.
If the resistance is low, replace control unit.
Additional information:
- To access the relay/fuse box in the boot, see Integrated relay/fusebox 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
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.
If the function is now OK, the fault was caused by a short-circuit in the relay driver circuit.
Was the function OK?
Yes - Verification completed
No - Trouble-shooting information
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Trouble-shooting 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 the components
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