Keyzmama

Good day,

Car threw code P0135 - O2 heater circuit malfunction.

From what I understand the heater on our O2 sensors helps warm up the zirconium sensor, for the O2 assembly to start operating sooner than it would if it was just warming up due to exhaust gases.

Since the code is referring specifically to the heater circuit and not the sensor itself, I was wondering if it means that my primary O2 sensor still works as intended, just takes a bit longer to get to the operating temperature. I haven't noticed any adverse symptoms to indicate O2 sensor not working - no hesitation, stuttering, rich exhaust smell, or excessive fuel consumption (this last one is hard to judge as we've had a cold spell here in Ontario).

Hope there are some O2 experts that can chime in. Thanks!

TexasHonda

You have an air/fuel sensor rather than O2 sensor but should work when fully warmed. Early on, no O2 sensors had heaters.

Check Engine Light will stay on and you will not be able to pass any emissions test. Continuous CEL will mask any new problems and potentially lead to complications.

good luck

Keyzmama

Thanks for the response. I'm aware that it's a AFR sensor, I wonder why the code guide calls it O2 sensor. I have a new one already waiting to be installed once the weather warms up a bit.