Faulty Signal. Permanent Fault

Faulty signal. Permanent fault

EFI-212 Front heated oxygen sensor (HO2S), signal

Checking front heated oxygen sensor (HO2S)








- Ignition off.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Disconnect front heated oxygen sensor (HO2S) (black connector).
Connect an ohmmeter between heated oxygen sensor (HO2S) connector terminals 3 and 4 (heated oxygen sensor (HO2S) side).









The ohmmeter should read 50 ohms - infinite resistance.

OK - Checking for a short-circuit
Check cable between front heated oxygen sensor (HO2S) terminal 4 and engine control module (ECM) #A32 for a short-circuit to the cable between front heated oxygen sensor (HO2S) terminal 3 and engine control module (ECM) #A33. Then continue with Verification.

Not OK - Try a new front heated oxygen sensor (HO2S). Then continue with Verification.
Replacing component

-------------------------------------------------

Checking for a short-circuit








- Check cable between front heated oxygen sensor (HO2S) terminal 4 and engine control module (ECM) #A32 for a short-circuit to the cable between front heated oxygen sensor (HO2S) terminal 3 and engine control module (ECM) #A33.

Continue - Verification

-------------------------------------------------

Replacing component
- Try a new rear heated oxygen sensor (HO2S).





Continue - Verification

-------------------------------------------------

Verification




Verification

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












- Ignition off.
- Front and rear heated oxygen sensors (HO2S) connected.
- Control module connected.
- Disconnect the Volvo Scan Tool (ST) from the VIDA station and use it in stand-alone mode.
- Start the engine and idle it.
- Go into the Diagnostic Test Mode (DTM) menu.
- Watch EFI-153 and EFI-212. Wait until the status of EFI-153 and EFI-212 switch to tested. This can take up to 15 minutes after the engine has been started.
- Read off diagnostic trouble codes (DTCs).
This can take up to 15 minutes after the engine has been started.

If EFI-153 or EFI-212 are stored they should have intermittent status.

OK - VERIFIED

Not OK - VERIFICATION FAILED

------------------------

VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

-------------------------------------------------

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

------------------------

Attempt New Test - Checking front heated oxygen sensor (HO2S)

-------------------------------------------------