speedo is calculated from wheel speed sensors, but missing sensor data should cause the ABS light... is ABS bulb ok (light on at start)?

 

yea the abs light is on, so is the ets light

 

OK. So when will we hear the whole story?
From what I heard the speed sensors are very reliable, but most common problem is dust/dirt accumulation on the sensors and the axles gears as well.
Start with taking the wheels off and have good supply of brake cleaner and toothbrushes.

 

Could the speedometer be broken?

 

The rpm sensors are just that, all the control modules that need to know speed, calculate their requirement based on the rpm being sent.

If you had a faulty rpm sensor I believe your dash would light up, plus you could possibly have shifting issues-------------you don't have those issues!!

Do all the other features of your IC work---water temp, fuel tank, IC back lighting.???

Before I started to clean off anything----I would find out what is wrong----To do that requires a local shop with good MB diagnostic capabilities---not a guy with a hand held scanner.

Sometimes the solution is not that simple?? An instrument cluster ain't cheap!!


Upon checking further----all four speed sensors would have to fail for the speedo IC computer to read "0". Additionally the traction control modules are the modules that provide the rpm data for the IC via the CAN. Therefore it could mean that the data is not getting to the IC. Then your IC needle is driven by a very special stepper motor!!

 

if you had a faulty rpm sensor I believe your dash would light up, plus you could possibly have shifting issues-------------you don't have those issues!!

HI i know its a bit late but this is the exact issue im having including limp mode.....could u please suggest where to start

 

Hello everyone. I am new to the site and was looking for the latest problem with my mercedes and this seems to be it. I apologise in advance if i am just refreshing an old thread. That isn't my intention. I just never found a conclusive answer. I have a 2003 SLK320 with the 6 speed manual transmission. My speedometer stops working sometimes but works other times. When it is hot outside and sunny, it always works. When the sun isn't beating down on my car and the engine isn't warm, it usually doesn't work. The temperature seems to be the key wether it works or not. When the speedometer stops working, many warning lights come on. The are the parking brake light, brake wear light, bas/esp, abs, and maybe one more i am fogetting. Also,the traction control doesnt work. I have heard that the wheel speed sensor could be responsible, but i have saw posts about other things that could be the problem as well. I would like to try to avoid a $1000 bill or more to take my car in and have them change whatever sensor might be causing it. I was wondering if. Anybody knew where the wheel speed sensors were located so i could see if cleaning around the area could solve the problem. Any feedback would be much appreciated. I can answer any more questions you may have about the problem. Thanks.

 

I would advise you to go to the appropriate forum... Also update profile including car type, location, etc...

Goodluck