Signal Too Low. Permanent Fault

Signal too low. Permanent fault

Checking the signal cable








- Front heated oxygen sensor (HO2S) connector disconnected
- Ignition on.
Connect a voltmeter between connector terminal #4 on the heated oxygen sensor (HO2S) (control module side) and ground.









The voltmeter should read approximately 0.5 V.

OK - Fault-tracing information

Not OK - Checking the signal cable

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Fault-tracing information





Checking intake system

Checking intake system
Check the intake system for air leakage according to intake system/leak test Intake System/Leak Test.

Was a fault detected?

Yes - FAULT FOUND

No - No Fault Found

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FAULT FOUND - Verification

No Fault Found - Defective heated oxygen sensor (HO2S)

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Defective heated oxygen sensor (HO2S)
Try a new heated oxygen sensor (HO2S). See Replace the front heated oxygen sensor (HO2S) Replace The Front Heated Oxygen Sensor (HO2S).

Select Continue.

Continue - Verification

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Checking the signal cable
Check the cable between heated oxygen sensor (HO2S) connector terminal #4 and engine control module (ECM) connector terminal #45. Check for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault.
Remedy as necessary.













Select Continue.

Continue - Verification

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Verification




Verification

Verification

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








- Reconnect the connectors, reinstall components etc.
- Connect VCT2000
- Start the engine. Let the engine idle until it reaches operating temperature.
Read off the signal for the front heated oxygen sensor (HO2S).





Does the value oscillate between approximately 0 and 1 V?

Yes - Resetting the adaptation

No - VERIFICATION FAILED

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Resetting the adaptation

Hint: 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.





Select "Continue" when the fuel trim is reset.

Continue - VERIFIED

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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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - No Fault Found

Attempt New Test - Checking the signal cable

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