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The size of a thin cigarette

thanks (never seen blasting cap,good thing)

If you are getting an ABS light AND....

a code that states speed sensor, then follow my suggestion for removing and cleaning / replacing the sensors that are located at the front right wheel and left rear wheel.

The other speed sensor is on the differential and reports the true speed of the car to the engine.

I think that the problem is the wheel sensors.

Scott Pettit

The sensor, itself, is about the size of....

a blasting cap or thin cigarette. Once it is unscrewed, look at the bottom end and you will probably find a build up of grease and dirt. It will take some doing but all of that needs to be cleaned of. Under the mess, you should see two small strips of metal that look like an = sign. Make sure that you gently clean these. I used a wire brush.

Before you put the the sensor back in, I suggest that you use a compressor to blow out the dirt near the mount. Also, clean all of the sprockets / teeth on the speed sensor wheel.

Scott Pettit

There's not points in the classical sense....

The hall effect sensor opens and closes like points based on the presence of metal of the sensor wheel. If dirt gets between the sensor wheel teeth then the sensor doesn't pick up the proper speed of the wheel and the ABS/DSC computer sets an error. Also, sensors can go bad, it's rare but it does happen. So if cleaning the sensor wheel and sensor doesn't solve your problem you might want to have the sensors checked and possible replaced. Goo luck.

Ja_Spur

did not see any contact points ABS (magnet)

It sounds to me that if anything could be the problem its contact points. Having owned a number of old Britsh cars,cleaning points and checking for major oxidation on primary wiring(secondary and thirdary as well.) that was a daily routine more frequent than needing gas.)

I just would love to find these contact points but I saw nothing at the wheels, that looked like points. The only thing that i think could have contact points on my car is that speed sensor on the differential. Its plastic and embeded into the dif. (looks like a major culprit in my opinion. But I don't want to mess things up any worse than they are.

Please clarify once again on location of these contact points, specifically these points and where they are(thanks)sorry if I seem confused. Its just I saw nothing that looked like points at the wheels but maybe I was not looking hard enough.

Do what I suggested in my earlier post..

as it is easy and may resolve the problem.

Scott Pettit

thanks for the info... what about the speed sensor

The speed sensor is whats coming up on the Code. Yet its the ABS/DSC thats not working. Just where is it that there are some "points" (contact points) involved. I'd like to check them out too.

this all broke on me last winter, when there was ice on the roads here, and I started spinning the tires then the ABS/DSC would kick in and drop me into a low RPM range. after repeating this a couple of times the thing(s) stopped working.

I just checked with RL Bentley....

The main difference between between the ASC and DSC is the module, with the addition of sensors, ie. steering, transverse acceleration, RPM rate, and tire pressure. Check and clean the other two sensors, remeber to clean the pulse wheels too, and if that doesn't do it look into getting new sensors.

Sorry, I am referring to the ABS sensors...

and there ARE 2 thin metal "contacts" on the tip.

In fact, I think that I will pull mine this weekend and clean 'em.

Scott Pettit

2000 Z3 2.8L with DSC

your right about the break sensors being opposite wheels, but I was for some reason thinking the ABS was as well,, (the light dawns on marblehead)

so it could be either or ...on the other two wheels as for repairing the sensors and this DSC is from what I gather tied into the system as well.

MY code is coming up saying its the speed-sensor. Is that the part with the ppoints in it I should be looking at and cleaning as well?

To clarify

The ABS sensor is a hall effect sensor that reads a toothed wheel on each wheel bearing. If you are seeing a sensor only on opposite corners, that is the brake pad wear sensor.

The ABS sensor slips into a hole in each wheel hub, and is kept with a 5mm allen bolt

What's your model year???

I'm pretty sure that all Z3 coupes are '99-'02. They'd have the ASC+T with four wheel sensors. The alternate sensor on the RF,LR would be the brake wear sensor. Four wheel speed sensors linked to a gyro is how the chassis computer detects and corrects a skid.

I just checked my Service Manual, '98 and up all have a speed sensor at all four wheels.

Re:ABS sensor /speed sensor

the speed sensor is what's coming up at the inspection. I'm confused though because the speed sensor I thought was whats attached to the differential and the abs sensors are frnt left wheel and right rear wheel, which I replaced one and cleaned the other.

I saw no contact points on the wheel sensors so your saying its the differntial sensor I should pull apart and clean.. hmmmmm (can do, if thats where I should head next)

Have you cleaned the speed sensors?...

I have had the ABS light on in the past and pulled the 2 speed sensors and cleaned them. Be sure to take a compressor and blow out the hole that the sensor is in. You will be amazed at how much dirt gets trapped around the sensor. When you clean the tip of the sensor, make sure that you clean to the point of exposing the 2 contact points on the tip of the sensor. Shine them up a bit while you are at it. Then, clean the plug where the sensor connects and spray it with some contact cleaner. Radio Shack sells it.

The whole process takes about 30 minutes for both of the wheels.

This should clear the light.

ABS light on as well as engine light

this is an old problem I have yet to solve without (it seems) replacing everything that makes the ABS/DLS system work.

Personally , I don't care if I have ABS. The problem is it makes tghe engine light go on and thats stopping me from getting an inspection sticker.

the code coming up is "speedsensor" and from what I have been told it all ties together.

I want to separate it, or bypass it... what ever it takes to get that engine light off.

from what I am hearing this ABS failure is becoming a problem in all brand cars, never mind our Z3's.

I have a Coupe thats why I"m not in here much.