Hello,

I have a 2003 R53 and I am currently getting the "trifecta" illuminating on the dash (ABS light, DSC, and tire pressure).

I have looked at all 4 wheel speed sensors.

I looked at the sensors with a scope: all 4 wheel speed sensors are getting about 13V DC, Has a 0.2 V square wave on the output when rotating each tire.

Now some of the sensors on the car may be aftermarket (not OEM). My question is, could anything else be causing this "trifecta" illumination?

 

As an update: The three lights only illuminate if I reach speeds in excess of 10mph. If i drive constantly below 10mph, none of the three lights will turn on.. .does this point towards anything?

 

Not sure about the MC, but in BMW's of similar vintage, those symptoms often point to a bad ABS module if all the wheel sensors check out. Solder joints go bad over time. Repair is about $200.


Regards,
Jerry

 

Wheel speed sensors or wheel bearings are the usual cause of the trifecta if you have already verified that there are no wiring issues, or exposed wiring.

My car had an occasional DSC/TPMS light with no codes stored as to which location, and it would go out whenever it wanted, turned out the problem was the tone ring on the LF wheel speed sensor.