Traction control light always on/dim ABS light

[chrissummit]

Hi All, I have a 1998 318ti sport, manual, DASC, lowered, with 4 17x8.5 (wide) contours. I am having a problem that is getting worse every month.

It started with the ASC light occasionally coming on last summer. It would happen after a few minuites of driving and go off after I power cycled the ignition. It went away about the time I put on my winter tires, so I figured it was related to the mix matched tires sizes I ran last summer. (fixed this summer)

This summer my airbag light came on and the code was for a seatbelt sensor that I have not fixed yet. Easy enough, but here is where it gets weird.

In the last few weeks, my airbag light started to dim. Fairly substantially. In some light conditions you can hardly tell if it is on. Then my ASC light started coming on, but far more often than last year and power cycling the ignition does not always help. Then the car started losing power as if the ASC was kicking in, and it shakes the whole car.

When I pulled the OBDII codes I got a 300, 301, 302, 303, 304. These are cylinder misfires. This seems to happen far more when the car is cold or under constant medium or heavy throttle. The boost stays consistent when this happens, so the ASC is not engaging the throttle plate thing under the hood. (although it feels like it)

Any ideas of where to start?

[mohaughn]

Sounds like you have three or four different problems that you need to diagnose as separate issues...

The airbag light is obvious, and an easy fix... For the ASC check out the usual suspects, speed sensors, ABS sensors, relays, etc... It is common for the ASC light to go off when you turn the car off, and come back on after 5 minutes or so. This is because the car has to be moving for the computer to check out the ASC system. Get the ASC light on, and then have somebody with an code reader capable of pulling ASC codes to read the code for you...

As for the misfires... Starting with a tuneup if the car hasn't had one in a while is usually a safe bet. There are tons of articles out there for troubleshooting misfires and funky idles.


I do have to question those codes though.. 301, 302, etc.. are not OBDII codes.. Those are always like Pxxxx, four digits... Those look more like BMW codes...

[chrissummit]

I will have the ASC codes pulled and see what I find. The car has been running great, and then when the ASC light came on it started the missfiring. Is is bad. It really feels like the ASC is kicking on..off..on..etc.

Any thoughts on why the airbag light would be dim?