Signal Missing. Permanent Fault
Signal missing. Permanent fault
Checking for contact resistance / oxidation
- Ignition off.
Remove relay 2/17. Check the relay base switches. Check for contact resistance and oxidation Also check the connector (54/3). Check for contact resistance and oxidation.
- Install the relay
- Activate the relay, press the horn.
If the function is now OK the fault was caused by a contact fault in the relay base.
Other information:
- For further information about the fuses and relays, see the Wiring Diagram
- Checking wiring and terminals Checking Wiring And Terminals.
Was the function OK?
Yes - Verification
No - Replacing the component
-------------------------------------------------
Replacing the component
- Ignition off.
- Replace relay 2/17
- Activate the relay, press the horn
- If the function is OK (the relay makes a noise), the cause of the fault was a defective relay (open-circuit or short-circuit the relay).
Other information:
- For further information about the fuses and relays, see the Wiring Diagram.
Was the function OK?
Yes - Fault Found
No - Checking for an open-circuit between the control module and the relay
-------------------------------------------------
Checking for an open-circuit between the control module and the relay
- Remove relay 2/17.
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 markedly, check the voltage between terminal #2 and the battery and between terminal #1 and ground. Both must be the same as the battery voltage.
Also check the signal loop between relay terminal #2 (2/17) and central electronic module (CEM) terminal #19A. Check for an open-circuit.
Other information:
- For further information about the fuses and relays, see the Wiring Diagram
- Checking wiring and terminals Checking Wiring And Terminals.
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:
- For further information about the fuses and relays, see the Wiring Diagram
- To access or replace the central electronic module (CEM), see Central electronic module (CEM), replacing Central Electronic Module (CEM), 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, press horn.
If the function now operates, this means the fault was probably caused by a short circuit to ground in the relay.
Does it work?
Yes - VERIFIED
No - VERIFICATION FAILED
------------------------
VERIFIED - Fault Found
VERIFICATION FAILED - Diagnostic trouble code (DTC) information
-------------------------------------------------
Diagnostic trouble code (DTC) 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 for contact resistance / oxidation
FAULT-TRACING FAILED - No Fault Found
-------------------------------------------------