Signal Missing. Permanent Fault

Signal missing. Permanent fault

Checking 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. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault
- Reinstall components, reconnect connectors etc.
- Start the engine and let it 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. The signal should be free of disturbances and above 0.6 V or below 0.3 V.
If signal is now OK this indicates that the fault was caused by poor contact in the connector.

Other information
- To access/replace the heated oxygen sensor (HO2S), see Replacing lambda probes, B5234T9, B5244T7 Replacing Lambda Probes.
- For information about signals, see Signal specification Signal Specifications.













Is the signal OK?

Yes - FAULT FOUND

No - Checking wiring and components

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Checking wiring and components
Check the signal line (+) between the heated oxygen sensor #4 and the control module #A61 (#B1) as well as signal line (-) between heated oxygen sensor #3 and the control module #A62 (#B2) for open circuit, according to: Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault
If wiring is OK, try another heated oxygen sensor (HO2S).
Remedy as necessary.

Other information
- Connecting the breakout box/accessing the control module, see Connecting the breakout box, B5234T9, B5244T7 Connecting The Breakout Box.
- To access/replace the heated oxygen sensor (HO2S), see Replacing lambda probes, B5234T9, B5244T7 Replacing Lambda Probes.
- For information about signals, see Signal specification Signal Specifications.














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 - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - FAULT FOUND

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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 connector

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