2008 H3 Alpha, just threw a P0036 code. Cleared it, and it came back mid-driving 2 starts later.

I know its Heater Oxygen Sensor Control (HO2S) Circuit (Bank 1, Sensor 2).

I have the O2 replacement sensor already (Bosch, from before). The originals are still on there and im at 190,000km so I'm thinking it may be due for a replacement.

Would replacing it fix this code?


Bank 1, sensor 2 is driver side rear O2 right? Could be wrong i always forget the sides.

 

You got the right oxygen sensor Bank 1 Sensor 2, or driver side post cat. By the code there is a problem with the heater circuit. Probably the O2 sensor. Replace that first. If the code persists with a new sensor you will have to look further. Not sure, but there might be a relay or fuse for the heater circuit. Faulty new O2? Try changing it with the passenger O2 to see if the code changes. P0060? Hope that helps.

 

Thanks. I put a brand new O2 sensor on, cleared the code, and it came back mid-drivre first drive after doing the change.

Anyone know if theres a relay/ fuse for the heater circut for that bank 1, sensor 2 o2 sensor?

 

I replaced the ACdelco original Bank 1 Sensor 2 o2 sensor with a Bosch 15282 direct fit replacement. I cleared the code and am now getting P0054---still for heater circuit. What are the chances the replacement could be defective right off the bat? What else could it be?

I took it into a mechanic but he was insistent Bank 1 Sensor 2 is PASSENGER SIDE downstream--according to his professional diagnostic software. I said no, as several people on this forum have indicated that Bank 1 is DRIVER SIDE. He ended up just leaving it as is and no work was done.

Does anybody have any idea what could be causing this?

 

The wiring harness to the O2 sensor should be looked at very carefully to see if there is fraying, cracked insulation, if it is rubbing on something, etc....

 

I'll bet bagels to beakers that it's the cat's.

 

i'm starting to think so. electrical tests find nothing wrong. I'm going next week to my exhaust guy who wants to put 2 high flow magna cats in. I might have him lose the back 2 cats as well, just have the 2 magna flows (the monitored ones). i'll let everyone know how it goes

 

Any updates on how this worked for you?

 

I went to see my Exhaust guy last weekend to get it done, and after looking more specifically into the setup and taking measurements he advised against doing universal cats---thought it might cause problems with the check engine lights and ECM configuration. So only option was to order the new cats. He couldnt find them anywhere through his suppliers so he told me to order off RockAuto, said that was best bet. so i did and am waiting for them to come in (Eastern Catalytic, left and right). He estimates 4-5 hours to install, which seems ok compared to a few other quotes of 6-7 hours and the GM dealer which said 10 hours! LOL. They also wanted $2200CAD for the right and $1600 CAD for the left converters...STEALERSHIP!

 

I'd say your guy is correct too.
I went with the Magna Flo cats and I'm getting the check engine light even with adding new O2 sensors with the new cats.