Permanent Fault, Signal Too Low

Permanent fault, signal too low

Checking the signal cable








- Ignition off.
- Rear heated oxygen sensor (HO2S) connector disconnected.
- Ignition on.
Connect an ohmmeter between heated oxygen sensor (HO2S) connector terminal 4 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 5 V.













Is this reading OK?

Yes - Defective heated oxygen sensor (HO2S)

No - Checking signal cable

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Defective heated oxygen sensor (HO2S)
Try a new heated oxygen sensor (HO2S) according to Replacing lambda probes Replacing Lambda Probes.

Continue - Verification

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Checking signal cable
Check cable between heated oxygen sensor (HO2S) connector terminal 4 and engine control module (ECM) connector terminal 44 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault.
Remedy as necessary.













Continue - Verification

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Verification








- Reconnect connectors, reinstall components.
- Connect the VCT 2000.
- Start engine. Idle the engine until it reaches operating temperature.
Read the parameter lambda PROBE2.





Does the value oscillate between approximately 0 and 5 V?

OK - FAULT FOUND

Not OK - No Fault Found 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 signal cable

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