ASC Issues

[mdlane72]

Hello-- I have a 98 318ti and have been having an ASC problem. I could care less about having the ASC system work. I am having terrible surging at cold, hot, driving on the freeway, in traffic-- and its intermittent. I can do the battery off the post for a night and it goes away the light goes off and all is right with the world-- then I feel the surge, the light goes on and its bucking again. Its just terribly annoying and bad on the mileage-- which is the reason for buying it in the first place! The car has 180k on it now if that matters. It doesn't seem like when I unplug the ASC motor on the drivers inner fender that anything better happens and the ABS light of course comes on. I have taken it to a BMW guy -- which I have serious doubts about-- and I remember on his scanner it mentioned something about the brake light switch being an issue. Is there any way that within the wiring that the system passes through the $15 brake light switch and is kicking my butt? I have a friend with a 02 Accord and the brake light switch did a lot and fixed many issues-- just wondering if thats my problem. I dont want to just throw parts at something and hope to fix it.

Thanks for any help,
Matt

[adrnln]

i've encountered this before on my 98 ti. in the past it has been my 2nd'ary (ASC) throttle position switch. unplugging it won't help...you need to replace it. to test my theory disconnect the plugs to the ASC/ABS computer under the glove box. to access remove the panel under the glove box and it's the silver box closest to the door/fender. it should be clearly labeled. if the car runs fine w/o the ACS/ABS computer i'd replace the ASC TPS.

i know you don't care about the ACS but...the part is only $70-80

Sheridan

[mdlane72]

Thanks for the info..I was about to go and just start replacing sensors. Funny thing happened ..I replaced the cooling fan last night and while the lights are still on I am having no surging issues. I have heard of fans causing issues of all kinds in the past but it just might be on a good day is all. If it starts up again I am swapping the sensor. Do I need to have the codes cleared?

Thanks,
Matt

[mdlane72]

Fan wasn't it :-) off to get a new sensor tomorrow!