I just got this code : P0036.

Autozone describes it as follows:

Heater oxygen sensor - Bank 1 Sensor 2

Poor electrical connection
Failed H02S12 (Bank 1 Sensor 2)

I checked the connections, they seem fine.

I know there a 2 sensors, but I don't know which one I should replace.

 

You have 2 sensors on the mini's exhaust.

B1S1 is the sensor that is pre-cat, or bolts to the manifold before the catalytic converter.

B1S2 is the sensor that is post-cat, or after catalytic converter. Although, may be bolted directly into the side of the cat itself.

Jack up car and take out your metric wrenches. Otherwise you can always buy the right size o2 sensor socket and fit it to your ratchet.

O2 sensors are common issue on the mini's especially older models or higher mileage.

 

Thanks

Ya my car is about to clock 172000 miles. So it makes sence.

I thought it was after B1S2 was after the CAT. But the guy at Autozone confused the hell out of me when he tried to convince me that it was before the cat.

Thank you for the clarification.

 

He was asking about B1s2, you mentioned b1s1 and b2s2. Or is this just a typo?

 

Edited for typo. Good catch

 

P0036 is for HO2S Heater Control Circuit (bank 1 sensor 2)

So there is nothing wrong with the sensor itself. The problem lies in the heater wiring from the PCM to the oxygen sensor, or perhaps in the PCM itself.

You'll have to look up PCM electrical connectors and pin assignments and back-probe the connectors to check for continuity and then voltage drop them.

 

Although the universal code language defines this as a control circuit failure the O2 sensor is still part of that circuit.

http://engine-codes.com/p0036.html

Its much easier to unplug the o2 sensor and check resistance across the 2 heater pins for open circuit than trying to check voltage drops or the connector to ECU pins.

Despite the language used to define this universal fault code, the O2 sensor is the overwhelming typical culprit.

 

If you do in fact determine the O2 sensor (or sensors) need replacing, please don't buy Bosch. They do not have the proper resistance built in and will cause your ECU/PCM to display codes. You can find links to all the info you need from this post I made in another thread awhile back: https://www.northamericanmotoring.co...11-post28.html. The link for the NTK part is still good.