Signal Too High. Permanent Fault

Checking Signal Cable
- Ignition OFF.
- Disconnect heated oxygen sensor (HO2S) (front heated oxygen sensor: black connector, rear heated oxygen sensor: gray connector).
- Ignition ON.
- Connect a voltmeter between the heated oxygen sensor connector terminal 2 (engine control module (ECM) side) and ground.
- The voltmeter should read approx. 0 Volts.

If reading is OK:
^ Try a new heated oxygen sensor.
^ Proceed to: Verification section below.

If reading is incorrect:
^ Check cable between heated oxygen sensor terminal 2 and engine control module # A14 for a short-circuit to supply voltage.
^ Proceed to: Verification section below.





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

- Ignition OFF.
- Front and rear heated oxygen sensors connected.
- Engine control module connected.
- Start the engine and idle it.
- Go into diagnostic test mode menu.
- Watch the diagnostic trouble code to be verified.
- Wait until its status switches to tested. This can take up to 15 minutes.
- Read diagnostic trouble codes.
- If EFI-522 is stored they should intermittent fault status.

If reading is OK:
^ Fault corrected.

If reading is incorrect:
^ Proceed to: Fault-tracing Information section below.

Fault-tracing Information
The verification result shows that the fault persists.

- Do you want to exit fault-tracing?

Yes:
^ Fault not corrected.

No:
^ Proceed to: Checking Signal Cable section above.