Motor Vehicle Maintenance & Repair Stack Exchange is a question and answer site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

This auto has 22k miles and both sensors were changed a year ago about 2k miles with OEM parts. Can anyone tell me how to test these? they have 2 black leads a blue and a white lead. I have voltage to the connector on the black leads. My suspicions are that both of these new sensors can't be bad and my problem is something causing them to throw codes?

share|improve this question

P1135 A/F Sensor Heater Circuit Malfunction (bank 1 sensor 1)

P1155 A/F Sensor Heater Circuit Malfunction (bank 2 sensor 1)

There are two conditions that set the code: heater current exceeds 8 Amps or below 0.25 Amps.

This can be caused by: an open or short in the heater circuit, a bad sensor heater, or the ECM.

The sensors are grounded individually by the ECM, but are both fed power on the Black wire (Terminal 2 of the sensors) by the A/F Heater Relay (A/F HTR), protected by a fuse and a fuseable link.

Since both codes are present and both sensors have a common power source I'd check there first.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.