Car-2008 C350 sport RWD v6

I had a non Mercedes mechanic change my front driver side wheel bearings. After he was done my comand display had the message:

ABS and ESP Inoperative see operator's Manual

My mechanic is at a loss on the error message since he said he did the repair correctly.

now when I start the car and drive it I can feel my ABS kick in and then the error message would come up.

Anyone had similar experience?

Please be sure to post the solution to help others.

Some later cars use a magnetic wheel grease seal that triggers the ABS / ESP wheel speed sensor. If a standard seal was used it would not send a signal to the computer while the wheel is turning.

There is also a chance the wheel speed sensor wiring has developed a fault.

There are a few fine points in the diagnosis. We need to find out what the exact error code number and description is to go farther.

This is the first thing you want to look at. What did he do with the seals during the servicing of the wheel bearings? If it is not installed just right (or as already said, is not the right one) it will throw the ABS code.

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Jim

my mechanic gave me the old wheel seals and I verified it is magnetic. I also confirmed the new one he put on is also magnetic since I have an exact spare. During the install he used a aluminum hammer to knock the wheel seal in place. I am not sure it he damaged it since he didn't know it was magnetic. I am not sure if the grease is magnetic grease but I assume so since it was part of an overall kit that had the magnetic wheel seal.

BTW, I read online my car has the dreaded SBC system and my mechanic should've disconnected my battery prior to the work. I wonder if that is causing the ABS & ESP message and the only way to clear it is to take it in to the dealership?

He should have disconnected the connector at the SBC unit. That could, very well have caused the code. If you can find someone with correct interface tool then it should be easy enough to reset.

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Jim

Shutting off the SBS is more for the safety of the person working on the car. If the door is opened , key turned on or brake pedal pressed, the system can wake up and pressurize the braking system.

And, the SBS system has a backup battery in addition to the regular battery that runs the rest of the car.

The grease will be standard wheel bearing grease.

A check that any shop can do is unplug the wheel speed sensor, attach a AC volt meter and spin the wheel. Both front wheels should produce similar voltage if not, have a look at the lower / non existent of the two.

I'm not sure if the error will clear by it's self if the fault is fixed, at minimum it will remain in memory for XX drive cycles.

I don't know that I'd call the SBS dreaded, there is much emotional response flying around out there in the face of data and logic.

I had my mechanic replace the wheel seal and this time he installed it with car and used a wood block to knock in the seal. the ABS and ESP inoperative error still persist. Anyone has other idea?

I've seen after-market wheel bearings cause this issue before. The inner bearing may not be pushed all the way onto the spindle. Even just 2 or three millimeters will make enough of a difference to throw off the wheel speed signal.......

Yes, stop randomly throwing parts at the car and perform a structured diagnosis.

You need to see what brake codes are present in memory.

I've seen bearing bores have too small of a radius due to a poor interchange chart. The radius is there so the spindle stub radius has some space.

The original poster says the seals / bearings / grease were part of a kit so that sounds like MB parts as aftermarket parts are usually piecemeal.

When I installed the first bearing it seemed to go onto the spindle fine. When I went to remove it to install the second seal the hub was a little hard to come off the spindle. I assumed suction from the grease or something. I installed the second new seal and put the hub back on and the message was still on the screen. What I thought was suction was the slightly undersized bearing sticking to the spindle and keeping the hub barely to far away for the sensor to read it.

I've done a lot of wheel bearings on a lot of different cars and trucks. This is one of those *If I knew then what I know now....* moments.

By the way I am the mechanic... This is just one remedy I found that someone else posted on another forum. Sorry I just copy and pasted here.


Im new to this website but not new to working on cars. vettdvr makes good points, you have to learn by doing and be safe at the same time. I also attempted to replace the bearings on the front hubs. Dealer was only showing the entire hubs as replacement, I tried to take another route and just get the bearing numbers off of the old bearings and install the replacement bearings with a new oil seal, (tone ring to mercedes) more on that in a minute. after unsuccesful attempts to get the ABS, ESP warnings off of the dash after installing the hubs with replacement bearings, I finally researched the bearings more. I only found the bearings that orinially came out of the hubs available from china.. the national bearing replacements were not an EXACT micro match of the old bearings, these newere bearings caused a difference in diameter or distance from the sensor in the knuckle which thru off the computer, hence my ABS, and ESP lights went off. I highly suggest that you buy the OEM mercedes hubs, they come fully assembled and ready to install with grease. just get your torque right on the spindle nut and you should be ready. Now the tone ring.... they call it the tone ring because it is a metal ring surrounded by rubber. this oil seal ring is installed same way as grease seal and it is used by the sensor to calculate your speed, ABS and ESP. so in short, I spent $80bucks on replacement bearings and then had to spend the cost of the new hubs on top of that. all is well now...

I decided to take my car to a strictly Mercedes repair shop where they had the STAR diagnostic tool. They did a thorough analysis of the car and they said there are no ABS brake codes. The only error came from the ESP where it said the possible cause is the multipole ring which is shop talk terminology for the wheel bearing seal. They cleared all the possible codes on the car and when they inserted the key into the car, the 'ABS & ESP inoperative' error message came up despite the car not moving. If I move forward with the repair with the shop it'll be the 3rd time doing the wheel seal. Should I just suck it up and buy a genuine MB wheel bearing hub that has the bearings and seal in it so I don't have to deal with the wheel seal issue? I'm at a point where this is a likely choice.

Hire the guy with Star machine to change the seal using MB part. If it is a mm out of position, either way, it will cause issues.

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Jim

I the car isn't moving, sensor / magnet position is meaningless.

You need to get a hold of a shop that knows how to use a scan tool. Given there was a wheel speed error ( we still need the exact code # and description ) the next step is to spin the wheel / drive the car and look at road speed for that wheel. If the wheel speed matches the other front wheel, the mag seal is good.

Another test would be to swap the hubs left to right, drive and see if the problem moves across the car. If yes, the problem is the mag seal, if not the problem may be a wheel speed sensor but be sure to test it / swap left to right before replacing.


The car might need to be driven after clearing the code so the system knows the sensors are working. ( I don't know this for sure but it is part of regular diagnosis. )



Stop randomly throwing parts at the car and perform a structured diagnosis.