[tire guy]

I've got a new to me 2011 335D, 70K miles, Service Engine Soon light popped up several months in;

4831 intake temp sensor
4BC6 intake temp sensor (ref for MAF)

cleared the codes, crossed my fingers, no dice back on shortly after,

went to BMW, picked up a new intake temp sensor, installed, cleared codes,
1 hour later, back on again

did some reading here and elsewhere, looking for clues, seems these codes can be related to the Mass Air Flow sensor, so I cleaned that, cleared the codes,
back on again

only strange thing we noticed when changing the intake air sensor, there was some (not alot) oil in the air tube. maybe turbo seals leaking some oil??

any help appreciated

[335dlci]

What sensor did you change when you mentioned there was oil in the intake tube? The intake sensor is built into the MAF sensor. There should be no oil and there is no way for oil to get in that part of the intake tubing.

[Yozh]

Both of your codes point to the MAF. There are two intake temperature sensors, one in the MAF and one on the cold side of the charge/boost pipe after the intercooler and before the throttle plate. That is the one you have probably replaced. If you have cleaned your MAF and it still is a no go, you need a new MAF. As a suggestion, you may wish to look at other sources of the MAF besides BMW as prices will be much better. Look for a generic Bosch part number 0 281 006 147. Look at ECS Tuning, FCP Euro or Amazon. You can also cross reference it to the BMW Part number 13628509725 to make sure you got the right thing. Consider replacing your air filter at the same time, if it has some extended miles on it. Please note that you will need to reset MAF adaptations as well as Mass Quantity adaptations as well. But you need BMW specialized software for that.

Oil misting in the intake system is ok on these cars. This is from the cranckcase ventilation system.

[sukutash]

I had same codes and new MAF sensor fixed it.

[tire guy]

Thanks for the responses,
we replaced the intake sensor in the air tube leading to the throttle plate (BMW # 13627812741)
Sounds like it's time for a MAF sensor.

"Oil misting in the intake system is ok on these cars. This is from the cranckcase ventilation system."

Thanks for the oil info, I like that answer much better than my guess/fear.

[tire guy]

installed a new MAF sensor & air filter, yesterday.
cleared the codes, 100 miles so far and no SES

thanks again for the help