Mercedes 1996 e300d abs light not working + rev counter not work

I would have thought maybe a wet body control ecu or somthing like that

You could have something else wrong such as abs sensor this will put the gearbox in limp mode you will need to get the car diagnosed with computor

check the condition and tension of the drive belt. Check that the battery terminals and posts are shiny clean and tight. Have the battery load tested for faulty cells. Have the alternator tested for output

This is just a traction control light.....If one wheel out spins the other it will make it come on at times ..You need a scan tool but you can disconnect the negative battery cable for 20 seconds and the light will go off......If it comes on again you will have to change wheel speed sensor...This is common with all vehicles with Traction control and ABS...Have it checked for saftey reasons...
But it happens with a lot of them.........Sensor replacement is normally what you have to do.
Sometimes battery disconnect works....You will have to reset clock.
Hope this helps..........................Metalpoet

Hook positives to positives on each battery, then hook negative to your battery and other negative to frame of other car.

Suspect idle control motor, although mass air flow sensor problems have sometimes been related to idle surge. Have pcm codes pulled for further diagnosis.

Your problem sounds as if the thermo sensor....which controls the air fuel ratio when engine is cold....is faulty. It is a common fault on this model.
This is not an expensive part, and takes only a short time to fit.
Good luck
John

sounds like the idle speed sensor,if your rpm's are idling up and down

you should be able to pulse the pump in actuator tests you can test the signal at the same time.your cruise wont work if the abs isnt working it takes the readings from the wheels,check your power and earths at the pump.

when the abs is activated it will cause the brake pedal to jump in and out rapidly, and the ABS light will flash at the same time, is this what u are asking? is this normal? yes.