Signal Too Low

Signal too low

Checking and replacing the component




- Ignition off
- Remove relay 2/158. Check the relay base switches. Check for contact resistance and oxidation
- Install the relay
- Ignition on.
Activate the relay.
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

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Replacing the component




- Ignition off
- Replace relay 2/158
- Ignition on.
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
- For further information about the fuses and relays, see the Wiring Diagram.









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




- Ignition off
- Remove relay 2/158
- Ignition on.
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.
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 voltage and between terminal #1 and ground. Both should equal battery voltage.

Hint: Do not forget to check that the power supply to the control module is OK.

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

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Checking the control module for short-circuits




- Ignition on.
Activate the relay driver.
Measure the resistance between terminal #2 and ground when the relay driver is active.
The resistance must be low when the relay driver is active.
Replace the control module if the resistance is high.

Other information
- For further information about the fuses and relays, see the Wiring Diagram.






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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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking and replacing the component

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