[efthimiz]

Hey,

I ran a search prior to posting but did not find any relative results on the forum or web to my issue. I recently completed an oil change and after a few days, the CEL lit up. I ran diagnostics a few times to ensure it was not a fluke but the same 2 codes come back, P0036 / P2270. When reading into codes, here are the results:

P0036 [0x0036]
Heated oxygen sensor (HO2S) 2, bank 1, heater control - circuit malfunction
HO2S Heater Control Circuit
Status: Confirmed
----------------------------
P2270 [0x2270] Archive (inactive)
Heated oxygen sensor (HO2S) 2, bank 1 - signal stuck lean
O2 Sensor Signal Stuck Lean
Status: Permanent

The only info I was able to source is that it could be contaminated fuel in the tank or a burn of excessive amounts of oil which can create deposits on the oxygen sensor.

I ran an oil service maintenance and checked levels which all came back good. I also checked the sensors and they look intact. The oil I used is Mobil 1 ESP Full Synthetic Motor Oil 0W-30 which is on the list as compatable.

Any suggestions or additional red flags I should be aware of before I begin replacing sensors and flushing oil with oem BMW oil?

Much Appreciated.

[Enabled]

I doubt the oil change caused it, unless you unplugged stuff(?). The oxygen sensor is dead when the heater circuit is fried.

Do you have a scan tool that can read BMW codes? P codes aren't always the best, although in your case it should be straightforward.

[Track/S]

If you didn't touch the connector, oxigen sensor probably died.

[Hank Scorpio]

Looks like O2 sensor is shot.

[efthimiz]

I just got back in town and appreciate your initial responses. I will run another diagnostic with a higher scan that provides hex codes since the 2 scanners I used only show p-codes. I have leaned on the sensor being shot as the most plausible outcome but I am just stumped on what may have caused it. I can only link failure of the sensor to the oil change and can confirm I did not disconnect anything. I am skeptical that if I replace it and the sensor dies again.

Alternatively, I ran a quick search and BMW's warranty disclosure is somewhat confusing. Here is the reference if anyone has input on warranty replacement (if any).

"BMW's front oxygen sensor is covered under an emission-related regulation for 15 years or 150,000 miles, whichever comes first." I have a feeling this stated warranty may be for a specific model but I may have to do some further reading to get clarification.

If I do need to come out of pocket, suggestions for a site I should purchase from? I know it's a very generic question which I can google but there is always a tried and test site most would probably use. Much Appreciated for any feedback.

[Enabled]

Following a better scan to see which sensor it is exactly, you can use these part numbers to find an equivalent original equipment, or OEM like Bosch

https://www.realoem.com/bmw/enUS/sho...diagId=18_1456


There are counterfeits everywhere, so make sure you get it from a responsible vendor. ECS Tuning, FCP Euro, AutohausAZ etc.