Signal Too Low. Permanent Fault

Signal too low. Permanent fault

Checking the connectors and components




- Ignition off.
Check the connectors for the rear heated oxygen sensor (HO2S) and control module for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the signal cable between rear heated oxygen sensor (HO2S) connector terminal #4 and control module terminal #44 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the intake system for leakage according to intake system/leak test Intake System/Leak Test.
Remedy as necessary.

Other information:
- To connect the breakout box, see Connecting the breakout box. EMS 2000 Connecting The Breakout Box. EMS 2000
- For information about signals, see Signal specification Signal Specification.













Continue - Checking diagnostic trouble codes (DTCs)

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Checking diagnostic trouble codes (DTCs)




- Test drive the vehicle for at least 10 minutes at a constant speed and throttle opening
- Allow the engine to idle for at least 5 minutes
- Read off diagnostic trouble codes (DTCs)
- Check whether the status of the diagnostic trouble code (DTC) has changed to intermittent. The status of the diagnostic trouble code (DTC) will have changed to intermittent if the fault has been remedied.





Has the status of the diagnostic trouble code (DTC) changed to intermittent?

Yes - Resetting the adaptation

No - Replacing the component

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Resetting the adaptation

Note! It is important that the fuel trim is reset after this diagnostic trouble code (DTC) is remedied. If this is not done there may be driveability problems, even though the fault is no longer present.




- Ignition on
- Click on the VCT2000 symbol to reset the fuel trim.





Continue - FAULT FOUND

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Replacing the component
- Replace the rear heated oxygen sensor (HO2S) according to Replacing lambda sond rear Removal and Replacement.

Continue - Resetting the adaptation

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Resetting the adaptation

Note! It is important that the fuel trim is reset after this diagnostic trouble code (DTC) is remedied. If this is not done there may be driveability problems, even though the fault is no longer present.




- Ignition on.




- Click on the VCT2000 symbol to reset the fuel trim

Continue - Verification

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Verification




Verification

Checking diagnostic trouble codes (DTCs)




- Test drive the vehicle for at least 10 minutes at a constant speed and throttle opening
- Allow the engine to idle for at least 5 minutes.




- Read off diagnostic trouble codes (DTCs)
- Check whether the diagnostic trouble code (DTC) status changes to intermittent

Has the diagnostic trouble code (DTC) status switched to intermittent?

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 - Exit fault-tracing

No - Attempt New Test

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Attempt New Test - Checking the connectors and components

FAULT-TRACING FAILED - No Fault Found

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