Signal Missing. Permanent Fault

Signal missing. Permanent fault

Checking the connector

Caution! Do not apply rust solvent spray or grease to the heated oxygen sensor (HO2S) 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 signal for the rear heated oxygen sensor (HO2S).

Note! It may take up to approximately 3 minutes before fuel trim has begun and the signal can be read off.

Check that the signal is within its permitted range. There must be no interference in the signal and it must be above 0.6 V or below 0.3 V.
If the signal is now OK this indicates that the fault was caused by a poor connection in the connector.

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, see Signal specification Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals.













Is the signal OK?

Yes - FAULT FOUND

No - Checking components and wiring

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Checking components and wiring
Check the signal cable (+) between heated oxygen sensor (HO2S) terminal #4 and control module terminal #A10 (#A10). Check the signal cable (-) between heated oxygen sensor (HO2S) terminal #3 and control module terminal #A11 (#A11). Check for an open-circuit.
Try a new heated oxygen sensor (HO2S) if the wiring is OK.
Remedy as necessary.

Other information:
- To connect the breakout box and 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 information about signals, 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.
- Reconnect connectors, reinstall components.
- Test drive car as follows:
A/C on
Drive the car so that idle, normal and high speeds are reached. Let the car operate in these phases for a few minutes.
Accelerate at full throttle a number of times so that high boost pressure is reached (applies only to turbo models).
Total test drive time must be 15 minutes.

Note! After test driving the engine should not be turned off. The test drive must be carried out again.

Connect VIDA again and read out the heated oxygen sensor (HO2S) 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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