[ZPC0001]

Hello friends,

I've been getting the following three error codes for a couple weeks now. I'm pretty sure it's an o2 sensor, but the codes are giving me mixed feelings as to which sensor may be bad. The codes are as follows:

118602- post catalyst sensor too lean (bank 1)
128301- sensor before cat signal biased/stuck rich (bank 1)
128401- sensor before cat signal biased/stuck rich (bank 2)

Car is a 2011 f10 550i.
Any help on this topic would be much appreciated!

[badblack550xi]

Originally Posted by ZPC0001

Hello friends,

I've been getting the following three error codes for a couple weeks now. I'm pretty sure it's an o2 sensor, but the codes are giving me mixed feelings as to which sensor may be bad. The codes are as follows:

118602- post catalyst sensor too lean (bank 1)
128301- sensor before cat signal biased/stuck rich (bank 1)
128401- sensor before cat signal biased/stuck rich (bank 2)

Car is a 2011 f10 550i.
Any help on this topic would be much appreciated!

list of mods would help

[ZPC0001]

Originally Posted by badblack550xi

list of mods would help

Car is completely stock.

[badblack550xi]

most likely bad censors.

[ZPC0001]

Originally Posted by badblack550xi

most likely bad censors.

I agree. Seems unlikely that all the sensors would go bad at the same time though. Just trying to figure out which one it may be and hoped somebody may have some experience with this

[Alimby22]

Did you ever get this resolved. I have the same issue

[Alimby22]

Anyone with this same issue that has a solution? Would really appreciate feedback here please.

[Thecastle]

Okay..... So this can be caused by multiple problems.

1st you can have an un-metered air leak typically after the MAF sensor. Make sure the hoses post maf are tight and attached properly.
2nd you can have a bad injector, pull the plugs and see if they're wet.
3rd and most likley your 02 sensors are bad and need to be replaced. Mine were toast at 57,500K miles and had to be replaced.
4th and least likely your plugs are bad or coil packs are bad and your getting poor combustion.

One other thing to check is that you do not have engine partition water leaks. Water leaking on to the 02 sensors can cause them to corrode and die.

[535_BiTurbo]

Originally Posted by ZPC0001

Hello friends,

I've been getting the following three error codes for a couple weeks now. I'm pretty sure it's an o2 sensor, but the codes are giving me mixed feelings as to which sensor may be bad. The codes are as follows:

118602- post catalyst sensor too lean (bank 1)
128301- sensor before cat signal biased/stuck rich (bank 1)
128401- sensor before cat signal biased/stuck rich (bank 2)

Car is a 2011 f10 550i.
Any help on this topic would be much appreciated!

I just got a 128501 and 118102 codes on my F10 550 today.

[coinage]

Also Getting the same errors, replaced both upstream sensors and reset adaptations. At idle, DME shows O2 Voltage stuck at 2.08 (13.16 AFR) which is too rich for idle. With engine running and getting voltages at the O2 connectors I am getting 2.22V (13.44 AFR) output to the DME.

Output from sensors are not matching the DME, o2's are not going into closed loop to trim...

Any Ideas??

[Aussie_550i]

Did anyone resolve these issues? I too have a 2011 550i. I have replaced all injectors with series 12, new coils and plugs, new pcv's and hoses, new valve stem seals. The engine is stock. The exhaust has factory DP's going to 2.5 with x-pipe then sports muffler then out the back.

Any ideas or solutions would be appreciated.

Thanks

[Aussie_550i]

Anyone have any ideas before i start throwing good money away diagnosing?