I recently replaced the downstream O2 sensor in my Toyota Camry. Shortly thereafter, the check engine like came on again providing the following codes:

When it comes to making these types of repairs, I'm a novice but am interested in resolving these issues on my own if possible.

My two questions are:

  • Does anyone know if P1135 and P1155 are related?
  • If so, will replacing the O2 sensor resolve both codes?
  • Can you tell us how this issue was resolved? I have a friend who's having P1135 on a 2002 Camry. May 4, 2013 at 2:50
  • It was indeed the air/fuel sensors. The thing is, you need to make sure that you get an AF sensor and not an O2 sensor. They are different and the former will clear the code, but the latter will not.
    – Tom
    May 4, 2013 at 17:44
  • My Toyota has a similar defect an I could not fix it. May I ask you, How did you resolve your problem?
    – user7565
    Nov 19, 2014 at 19:49
  • @paris this ended up being a bad spark plug that was mis-firing. i had to replace the spark plug and the head (it's reasonably easy and inexpensive to do, though any local autoshop should be able to do it for cheap, as well)
    – Tom
    Nov 20, 2014 at 1:33

4 Answers 4


P1135 Air/Fuel Sensor Heater Circuit Response (Bank 1 Sensor 1) is correct. I had the same code since 2010 until 2013. The day I changed O2 sensor 1 upstream for my 2001 Toyota Camry (4 cylinder, 2.2L) the code was cleaned, and then the engine light went away.


Both codes look to be related.

P1135 Air/Fuel Sensor Heater Circuit Response (Bank 1 Sensor 1)

P1155 Air/Fuel Sensor Heater Circuit. (Bank 1 Sensor 2)

Source: http://www.engine-light-help.com

Replacing the sensor may fix the issue, but as pointed out in the answer to your previous question:

it is not always the sensor that goes bad. Sensors read the mixture and efficiency of your combustion, and can trigger a code if you are running rich/lean.

Source: https://mechanics.stackexchange.com/a/2880/1554

Some additional information:


I have a 1st Generation (1995-1999) Toyota Avalon with a P1135 error also. I change the Denso Air Fuel Sensor P/N: 234-9007 and it solve the problem and the check engine light went away. I change it from the top instead of going under the car it was really easy. Hope this help like other have help me. Sensor Diagram


I too have a 2001 Toyota Camry. I also had issue with oxygen sensor. Replaced both upstream and downstream sensors. Still pulled code p1135. Was told to try replacing plugs, PCV valve, and to check for leaks between the O2 sensors on the exhaust pipe. Come to find out was give. The wrong sensor. The upstream sensor required one for California emissions. Finally got the right one and bang! No codes. Problem solved. Plus got new plugs and PCV valve. lol.

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