I had the 4 lights come on the dash couple days ago and took it to a mechanic friend who ran diagnosics with a snap-on reader. The "ABS", DSC triangle, "BRAKE" and something else, which I was told all come on together when the speed sensor is faulty. The code came up Right front speed sensor, we replaced the speed sensor and the the code does not go away ?? Anyone have any suggestions or have the same problem?? Thanks for the help in advance.
He has to reset the code.
Is it plugged in?
yes they we checked both of them and they are plugged in and he also reset the code as well.??
"ped.amini" wrote
Just curious... how many speed sensors does the e39 have? I thought there was just one near the right rear wheel...
Also, the speed sensor is integrated with the ABS module, so you replaced the whole module, right?
Thanks, Pete
4 - one for each wheel.
I suspect you have no idea how ABS/DSC works right? It compares wheel speeds. If it finds one wheel turning when other are slipping and the brakes are in use - it modulates the slipping ones using ABS. If it determines one of the rear wheels is turning faster than the other wheels in the car - it knows that wheel is slipping and it reduces speed on that wheel (with the throttle and brakes.) On later models it gets even more powerful, comparing the yaw angle of the car (rotation around it's axis) the G forces and the turned angle of the steering wheel to determine if the car is going where the driver wants it to go. If not - it uses dynamic braking on the wheels - individually - to correct.
It couldn't do this without 4 sensors right?
No it isn't. Wheel speed sensors are located (ta-da!) the wheels.
"admin" wrote
OK, I guess I was not clear in my question. What I meant to ask was how many sensors feed data into the speedometer in the dashboard?
Again, I was asking about the speed sensor that feeds the speedometer, not the ones that are used for ABS/DSC. Sorry for the confusion.
Pete
It's in the rear differential. It has a wire hooked to it and can be seen easily if you look under the rear of the car.
Not any more - they gave that up with the E34 series.
The ABS sensors are used to determine speed - everything is fed through the ABS/DSC module - including the signal to the speedometer.
What the original poster apparently doesn't want to accept is that the damn modules GO BAD... and give all the symptoms he's seeing.
You can drag a cow to water..
ABS/DSC controller.
Need to replace and get it recoded by tech with MODIC or GT1.
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