glennpaganetti

Hi,
I have a 2004 s500 4matic. got abs esp, etc code dash fault. computer showed faulty rear speed sensor so I replaced. Now all lights are off and no codes are showing. So, any ideas why the abs is engaging 100% of the time at about 20 mph and not spewing out any Codes ?

MJ50

moved to W220 forum...

Jack_88

What are your front and rear tire sizes?

cybertronicify

ABS engages when one or more wheels are not turning at the same (close to the same) speed. ESP however, will use the ABS pump to brake individual wheels to keep the car from getting out of control. For example, if you make a right turn and your front wheels start understeering, the ESP will use the ABS pump to brake rear right wheel pivoting the whole car towards the right to make correct the understeer. When you have different sized tires or wheels on your car, it can mistake it as you are losing traction and actively tries to fix the problem.

wallyp

For the ABS to engage normally, the computer must either have input that the brakes are on and a tire is skidding, or that the car is skidding.

We don't know if or how you cleared the trouble codes from the car. My first suggestion is that you need someone who has a STAR/DAS diagnostic system and knows how to use it well. The system will tell you what is going on. Most owners are startled when they first discover that a car with no check engine light and no warning will show dozens of trouble codes the first time that you hook up the diagnostic system.

None of the aftermarket code readers/diagnostic apps/etc. will read or correct a fraction of the items that the MB STAR/DAS system will check/test/correct.

glennpaganetti

Thanks for all your responses, here is an update. Had Transmission suspension shop run diagnostics (yes after maker reader). still no fault codes. but he was puzzled when driving the car hook up to the scanner when she hit 15mph while braking the computer froze every time then starting counting again as they accelerated. Almost time to go to dealer or mechanic with MB diagnostics. Any Guess's ?

SilberGrau57

I subscribed to this thread since I have the same condition: intermittent ABS, ESP message combined with ABS light on dash. Appears randomly, and resets usually after a restart. It is always accompanied by "Distronic Unavailable". Very rarely, I also get "Brake Service See Workshop" message.

Dealer scan shows stored right rear wheel speed sensor, but nothing concrete enough to recommend replacement. Since the warnings are intermittent, they recommend coming back for a re-scan whenever the light/warning is on.

kraut56

The right rear wheel sensor is the more common one to go, as it passes thru the floor pan above thru a bulb type seal, where the connector is.

Mine long time ago went, and when i pulled the rubber bulb seal down, water came with it.

Changing the sensor fixed everything related (I used MB part @ about $ 100.00).

Good luck!!

SilberGrau57

So it sounds like is a DIY after you get the part? My dealer quoted me about $483 installed. This is before my 20% MBCA parts/labor discount, so maybe closer to $390 with the discount applied. Still wondering about the DIY. I have access to a fully equipped auto shop, with lifts and tools, etc. Thanks for any guidance.

kraut56

It's one bolt holding the sensor to the axle, I believe 2 clips for the wire, pull down the seal bulb, disconnect the connector.
You got to do all that from below.

SilberGrau57

Thanks, I've got access to a garage with a lift, so I'll have a look underneath. I wanted to see what's involved in dropping the under engine shield to get to the engine oil drain plug anyway. I'd much rather drain the engine oil from underneath than suck it out from the top. I have access to auto hobby shop with all the tools for a traditional oil change, but not a pump to suck it out from the top.

So assume I can swap the wheel speed sensor, is there any coding/programming involved to getting it working again? This I do not have, either. A computer, that is.

kraut56

If you take the time to search and read the stickies on this and the other forum, all the answers on how to reset your faults are there.

It's quite simple.

Enjoy the forums!

glennpaganetti

Ok,
It fixed it self while in traffic in Brooklyn. LOL. Mystery still. But now the SRS light is on.
Love Mercedes. Thank you for your assistance. Im sure