Signal Missing. Permanent Fault

Signal missing. Permanent fault

Checking the connector




- Ignition off
- Check the heated oxygen sensor (HO2S) connector. Check for contact resistance and oxidation
- Reinstall the components, reconnect the connectors etc.
- Start the engine. Allow the engine to idle.
Read off the diagnostic trouble code (DTC) status for the front heated oxygen sensor (HO2S).
The text NOT READY is displayed if the diagnostic is still running.

Other information
- To access or replace the heated oxygen sensor (HO2S), see Heated oxygen sensor (HO2S), replacing Heated Oxygen Sensor (HO2S), Replacing
- For information about signals on 5 cylinder engines, see Signal specification Signal Specification
- For information about signals on 6 cylinder engines, see Signal specification Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals.













Is FAULT NOT DETECTED displayed?

Yes - FAULT FOUND

No - Checking components and wiring

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Checking components and wiring
Check the resistance of the heated oxygen sensor (HO2S) between terminals #3 and #4.
Check the signal cable between heated oxygen sensor (HO2S) terminal #4 and control module terminal #A18 (#A18). Check the power supply between system relay terminal #3 and heated oxygen sensor (HO2S) terminal #3. Check for an open-circuit.
Remedy as necessary.

Other information
- To connect the breakout box / access the control module, see Connecting the breakout box, B5254T2 Connecting the Test Box
- To access or replace the heated oxygen sensor (HO2S), see Heated oxygen sensor (HO2S), replacing Heated Oxygen Sensor (HO2S), Replacing
- For resistance values, see Component specifications Specifications
- For information about signals on 5 cylinder engines, see Signal specification Signal Specification
- For information about signals on 6 cylinder engines, see Signal specification Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals.













Continue - Verification

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off.
- Reinstall components, reconnect connectors etc.
- Start the engine and let it idle.
Read off the front heated oxygen sensor (HO2S) signal diagnostic trouble code (DTC) status.
The text NOT READY is displayed if diagnosis is underway.









Is FAULT NOT REGISTERED displayed?

Yes - Verification completed

No - 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 - Exit Fault-Tracing

No - Attempt New Test

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Attempt New Test - Checking the connector

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