Check Engine Light

So for over a month now, the check engine light (the yellow light on the dashboard shaped like an engine) has come on.... it stays on for like 2 days, then goes off for 2 days, then back on for 2 days, then back off, etc. No errors in the iDrive, no performance issues whatsoever.

I will have the dealer look at it when I bring it in for inspection next month, but what do you guys think? Faulty sensor somewhere?

It first appeared after I had the turbos replaced... but again, no performance issues whatsoever.

Happend to me a few weeks ago. Did a scan and it was the MAF sensor. If it is, take the MAF out and try cleaning it with a MAF spray cleaner. One of the easiest DIY you can do. Sometimes that is enough. Clear the light and see how it goes. If it comes back with the MAF code again then you have to replace it.

Thanks! Can you detail where the MAF sensor is and how to remove it?

Originally Posted by repoman75

Thanks! Can you detail where the MAF sensor is and how to remove it?

It's on the intake manifold near the air box. You have to remove 2 torx screws.

Here is a good post on it.

http://forums.5series.net/diy-do-you...diy-n52-98032/

Originally Posted by GSG1

It's on the intake manifold near the air box. You have to remove 2 torx screws.

Here is a good post on it.

http://forums.5series.net/diy-do-you...diy-n52-98032/

The n54 engine does not have a maf sensor.

Repo man, if your car is under warranty take it to the dealer for them to pull error codes or if you have a code reader pull the codes yourself. It could be numerous different things so the error codes will help narrow down the issue.

Originally Posted by booyaazaa

The n54 engine does not have a maf sensor.

...

Mass Air Flow (MAF) sensor measures the amount of air going in to intake. All cars need some type of mechanism to measure the amount of air going in to intake. Almost all modern cars have MAF - on some cars, it's located in an obvious place right after the air filter on the intake tube and on other cars it may be buried along the intake.

From experience if it is the MAF sensor it will give you performance issues, specially having turbos,
No disrespect, but if you do not know where to start looking for this sensor, take it to the dealer. Nothing better than knowing where to start looking based on a code.

Originally Posted by Gustavoerod

From experience if it is the MAF sensor it will give you performance issues, specially having turbos,
No disrespect, but if you do not know where to start looking for this sensor, take it to the dealer. Nothing better than knowing where to start looking based on a code.

Yes if you have a NA engine then you will have a maf sensor. But since the OP has a 08 535xi he has the n54 twin turbo engine that has a tmap sensor that measures temperature and manifold air pressure.

Originally Posted by booyaazaa

Yes if you have a NA engine then you will have a maf sensor. But since the OP has a 08 535xi he has the n54 twin turbo engine that has a tmap sensor that measures temperature and manifold air pressure.

Dealer it is I guess. And yes, NO performance issues whatsoever. And it goes off and comes back on almost regularly, every 48 hours.