I was getting code p036 and p050. The BMW tech said I need to replace oxygen sensors bank 1 postcat and bank 2 precat. I installed 4 new Bosch oxygen sensor. I got the now I am still getting code p036 and p050, in addition I and getting code p0172, p0175 and P00BC. Other than the tight fit they were easy to replace.
How can I put new sensors in and get more error codes?
These 4 O2 sensors are OEM Bosch numbers, not generic Bosch units and are each in the proper positions? Did you google the additional codes? Make sure you have every one in the proper position.
Any symptoms? Like a misfire or low power under load?
Yes, the are OEM Bosch. I got the numbers from the BMW tech and confirmed on Realoem.com I confirmed and it seems to be all installed correctly. Black wire 1-3 and grey wire 4-6. It does have a small misfire when I was sitting at a stop light. I added a little more anti-seized on the threads but I doubt that would cause the problem. I also checked my connector to make sure none of them was bent and I did not see any bent. It is very strange that I install 4 new oxygen sensors and get more error codes. He said that my valve cover is cracked and need to be replaced. However it was cracked before I install the new sensors and P0172, P0175 and P00BC did not come up before.
What model and year? '97 540i?........you're in the wrong forum.
How are you reading the codes?
If code reader has live data post fuel trims and post all of the codes.
Fix the mixture codes and the O2 sensor codes will likely go away.
P00BC = low mass air flow qty. Bad MAF or intake air leaks causing air to bypass MAF....cracked valve cover .
It was a cracked valve cover. I replaced the valve cover, fuel injectors and ignition coils. It seems to be driving much better. No more misfires.
I am driving a 2009 528xi. What do you mean by fixing the mixture codes?
P0172, P0175 are mixture codes. The cracked valve cover is causing fuel trims to be out of normal range because it causes air to bypass the MAF. Likely your O2 sensors were symptoms of fuel trim issue and not really bad.
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