Quote:
Originally Posted by mommy-of-4-kids
When I got the car, the speedo was not working. The ABS light was not on, however.
I took it to my BMW guy and he fixed the speedo problem. It was a module and not a sensor. He said that at least one of the wheel sensors (I gathered that there are several?) looked to have been newly replaced.
Although the ABS light was not on and is not on, an error is still coming up in the computer diagnostics indicating that there is some sort of sensor issue. My mechanic thinks that someone messed with the dash ABS light...
My BMW mechanic is actually the best in my city, works on BMWs that are raced, and known nationally. But, he admits that nav systems are not his thing.
Should I just have him go through the trouble of individually testing all of the wheel sensors? It sounds costly and time consuming...
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Fix the ABS!
It is a critical safety system!!
Each wheel has a wheel sensor,.
Each wheel sensor is connected to the ABS control unit
The ABS control unit then provides a speed pulse signal to the speedo, and another speed pulse signal to the nav computer
The speedo and nav computer do not necessarily use the same wheel signals (I could look it up more exactly if I new more about your car - post your chassis number)
Example: if the car is a 2000 E38, then it uses the wheel pulses from both front wheels (left and right).
These signals come directly from the ABS control unit.
The ABS control unit also connects to the warning light on the dash with one wire - so the wire has likely been cut to disable the ABS warning light.
But like I said - post your chassis number and I'll give you detailed fault finding instructions.
To determine if the ABS unit is fine, connect the BMW diagnostic computer and read out the faults inside the ABS control unit - if any wheel sensors are faulty, it will tell you. Quickly and easily.
And if anyone has messed with the ABS light, then fix it!
In almost every country in the world, the car will not pass a safety check if the ABS has been deliberately sabotaged to disactivate the warning light.