Hi there,

I currently have a failing wheel speed sensor in the front that I need to change, the part is on its way so nothing to worry here. In the meantime, the ABS light is always on, I got few malfunction messages (ABS, BAS, ESP, Pre-Safe) and my cruise control doesn't work as well. It feels like I don't have any power steering at all when I turn the steering wheel as soon as I put start driving the car. I know all these problems are directly linked to the speed sensor as I only have these when the sensor is faulty (it used to fail only when I exceeded 130 km/h but now it fails as soon as I start the car).

About 3 weeks ago, I also got a Airmatic ride height sensor that failed because the lever broke after a rough bump, so the front right end almost completely collapsed to the point I couldn't drive at all. Fortunately, I fixed it, but now I noticed that when the ABS sensor is faulty and all the previous problems show up (which currently mean "all the time"), the Airmatic system doesn't raise and doesn't drop either, it only stays at its "normal" level and pressing the buttons on the dash doesn't do anything. I still hear the normal "pssshhh" sound when I park the car and turn off the key and I also hear the pump working every now and then when I start the car, so I guess it's not an Airmatic problem. Now what I'm trying to figure out is weither or not the faulty ABS sensor is the cause of the Airmatic buttons not working. My theory is that since the Airmatic rising can cancel itself depending on the speed you are driving, it uses the datas sent by the speed sensors to determine when to lower the vehicle to prevent it from rolling over. Now since one of my sensor is bad and failing, it doesn't have all the datas it needs to adjust the suspension level, so instead of guessing and letting the system become potentially dangerous, it just doesn't work at all to prevent anything bad from happening. Now that's just my theory and I haven't had the chance to validate it yet and my mechanic didn't have the answer, so I would like anyone here who knows a bit about that stuff to tell me if I'm right or wrong.

Also, about a month ago, my blower motor failed (fortunately it's fixed) so I didn't had any A/C at all and had to drive with the windows down. During that time, I noticed that I could hear that "pssshhh" sound from the struts whenever I would come to a stop. Is that normal or is my suspension slowly dying ?

Thanks in advance for your answers !

 

I just posted in another section about my ABS light on while at the same time run flat indicator is inoperative as well as the cruise control. My post hasn't gotten any replies but it seems like it's more than a coincidence that the cruise stopped working the same time the ABS light comes on. It certainly looks like the cruise is related to the bad ABS sensor. How did you diagnose which sensor was bad ? Thanks and good luck, Will

 

The cruise control IS directly linked to the ABS sensors (also known as the wheel speed sensor) so it needs all of them to work properly to prevent the vehicle from skidding. If one of them fails, the system doesn't know the speed of the wheel it's linked to so it cannot work. I diagnosed mine with an OBD-II scan performed by a mechanic, but you can do it yourself if you have a professional tool for that (iCarSoft for example).

 

Hey guys, I received the new sensor today and replaced it, but unfortunately nothing changed and the ABS, BAS, ESP and Pre-Safe lights are still on the dash, plus I got the Airmatic visit workshop message while I was driving an hour ago. I tried unhooking the battery for a few minutes and turning the steering wheel to the left and to the right, but it didn't do anything except ****ing up my automatic windows.

Can anyone help me please ?

 

You will need to reset the windows and the sunroof. Hold each window switch in the down position for three or four seconds after the window is completely down, then hold in the up position for three or four seconds after the window is up. Do the same with the sunroof in the open and close position.

How did you know which sensor was failing? Do you have a code reader that will tell you if a sensor is faulty? Are you certain that you don't still have a failed or disconnected speed sensor?

It is very easy to mess up connecting the two plugs in the front wheel well so that they look perfect, but not truly making proper connection. One key is that they should be plugged in while held together.

 

Thanks for the tip, I figured that out last night while I was reading my owner's manual.

I didn't find out by myself which sensor was faulty, I bought the car with a pre-inspection done by a garage. Actually, they only scanned it with their tool and didn't do any serious visual inspection because I found out later that there were some problems around the wheels. But anyway, they did the scan and the code said it was the AV G wheel speed sensor (for "avant gauche" in french, means "front left"). But when I use a regular OBD-II scanner I don't get any code at all so they either cleared the existing codes or you need a professional scanner to read them.

But how do you make sure the two connectors are well plugged ? They look like they are well into place so it's hard to tell I guess.

I'm starting to think this could be related to other problems on the car. I currently have the two outer tie rod ends that are worn out (I got the new ones, just need to replace them), front lower control arms ball joints that needs to be changed and some control arms bushings in the rear axles. The mechanic also also told me I have play in the front axle but I think it's most likely caused by the worn out ball joints. The other thing is that I got a slight alignment needed because my steering wheel is not completely straight. Does any of these problems can be the actual cause of the warning lights ?

 

Yesterday, I removed the wheel and took out the two connectors to clean them and their plugs. When I put them back on, no warning lights AT ALL. I was like hell yeah, it finally worked. But after taking it for a test drive it came back on as soon as I started turning the steering wheel, except for the Airmatic warning which doesn't appear anymore (I guess the Airmatic sensor wasn't well plugged in with the speed sensor). My first thought was that the sensor didn't have enough play because it's shorter than the original one, so I took it out again and placed it in front of the strut so it wouldn't stretch too much when turning the wheel. It didn't work, so I took it out, cleaned it again, didn't work either. I tried to clean the original sensor and put it back on but the lights were still on. So I gave up for now, I'm clueless about what it could be. Is it possible that I damaged the plug while turning the wheel ?

The only thing that I saw is that the plug that connects the two sensors is a bit dirty. I tried to clean it but it doesn't go and I don't want to put any liquid in there.

 

 

But honestly I don't see how they could not be properly plugged, I pushed them in firmly, cleaned them... Is it possible that the bolt holding the sensor on the wheel has too much torque ? Because this problem used to be intermitent and would only come on when I would reach a high speed like 130-140 kph. But after the first time I removed it to investigate the problem, it became permanent and now it comes on as soon I turn the ignition on.

 

having similar issues with my CL class.. any news?

 

I replaced the sensor again with one from Delphi. I got my mechanic to clear the codes but they came back while driving, so it's likely to be the reluctor ring. I won't know it anytime soon because I'm storing the car for the winter.