I am a new member and have had my 335D almost 3 years. I love the car and have had very few issues so far. Purchased CPO with 22k and currently just over 60k. This week I got a check engine light while idling in a parking lot. Light stayed on through several key cycles but no drivability issues that I could tell. The local parts store shows a P0638 code. Which appears to be related to the the throttle valve. Car has been dealer serviced with 6k oil change intervals and strictly using only diesel fuel that has no bio.(two stations in my area offer straight diesel) I have added a can of seafoam to the fuel tank to see if that helps. Have any other 335D owners had this code? If so what was the issue? Parts? Cost to repair. Any suggestions for troubleshooting before taking to my local dealer? I really like the tech at my local dealer but I'm nervous that anything major will be costly now that I am out of warranty. Thanks Justin
As Mike Miller says, "BMWs are expensive to purchase, own and maintain". You're probably going to get more issues with your 335d that are more expensive than a throttle body so bite the bullet (I've got 120K and can tell stories!) The throttle on the M57 engine is used to shut off the engine if an over-run or some other problem causes a run-away condition. (Commonly would happen if the CCV failed and the intake started sucking motor oil out of the crankcase.) The throttle is a $400 part (http://www.realoem.com/bmw/enUS/showparts?id=PN73-USA-01-2011-E90N-BMW-335d&diagId=11_4263). But I would not change it, because it's not clear that that is the problem; you really need to get a BMW-specific OBD reader to interpret it, and someone knowledgeable to diagnose the problem. So pay the dealer their $150 diagnosis fee.
Thanks for your reply. I drove the car today about 250 miles without issue but the light was still aluminated each time I restarted the car. When I got home tonight, I ran out to pick up some dinner and the light did not come on when I started the engine and stayed off on its own. I will plan to make an appointment with my dealer this week to see what the issue may have been.
