Well, guess what: two days ago as I started my engine in a rest stop 15 miles north of Portland on I-5, I had all three of these lights (ABS, ASR and ESC) come on--only this time they wouldn't go out no matter how much time I gave between restarts. As it was late, I drove through Portland and overnighted at a Flying J, then went to MB Sprinter of Wilsonia the next morning at their opening time. The graciously looked at my Sprinter that day without an appointment, and discovered the left rear wheel speed sensor was not giving a signal. Of course, they didn't have one in stock, but ordered it to be delivered today. As of right now, I'm sitting here waiting for them to pull my sprinter back into the shop to change that wheel speed sensor.
I guess my previous episode was just the harbinger that this was to come. It wasn't just a fluke, even though when it was checked 200 miles ago the wheel speed sensor just hadn't yet fully failed as it checked out OK then.
The best part of this for me is that MB screwed up on this one: the odometer is sitting at 35,282 on this 2013 chassis, so it's still just barely under warranty!
Rock Doc
For info
On the 3500 the axle architecture you will find the sensor is mounted at 12,0 clock and protrudes into the case and "looks" at a small dimple hole formed in the outer bearing supporting the axle shaft (half shaft.) an the inner race track is the tone ring .
Its fairly long for a sensor having a body about 2 inched long under the mount flange.
You have to go easy getting them out because the stem section gets corroded where it sits in the axle and is easily sheered off if you are not mechanically friendly--other words ham fisted!
For the most part I have observed that they get knocked about as chassis cab at the body builders, crack and water gets inside the sensor guts over time!
The other hidden issue is that RV manufacturers use the sensor pig tail mounts and the wire hooks mounted on the axle to hold their electrical equipment wiring. It seems they cut the original zip ties off and re-bundlle it all leaving the senor wires strained, or they drop out of the mount hooks, and rub on the wheels, or get whacked by road debris.
The last as Eric has mentioned the hub bearing itself when it goes south excessive end play and debris corrupts the inner tone ring --basically a precursor to an axle shaft and bearing change out at $950 plus labor of about one to two hours.
The sensor is $180 a pop at the rear, plus one hour to install and clear with scanner and road test. The price you have mentioned seems high!!!! Unless the axle shaft is being changed out!
Dealers never keep wheel speed sensors in stock (maybe some have the odd one gathering dust for a 2500 at $125 each ) but 3500 are a "Nah mate no stock" So its a two day lead time to get and fix, a four day VOR if its happens on a week end!
I keep one of each sensor in stock for every Sprinter since the 2002 into for the very same reason as I have written here!
I suppose on a lighter note these sensor contretemps always seem to happen at the week end and public holidays like the 4th of July and Christmas prompting a call out!
Always it seems an RV going somewhere, usually it comes with a wife who for the most part is mature and voluptuous having brassiere reinforced with metal!
Upon successful completion and road test I often get the affectionate hug with the "thank you" as metal reinforced nether regions get forced into my upper neck area--most uncomfortable, but a necessary part it would seem of fixing Sprinters in an expedient fashion!
I supposed I have yet to meet any AMERICAN female "co driver" who wears Chanel #5--(usually reserved for English ladies who wear tweed or Burberry) simply implies & reminds me of "boxed ears", searing pain at the hand of an aunt when I was a kid; or ladies at church wearing the same perfume, and a draped fox stole with beady glass eyes! That bloody fashion item that always seem to be staring at me and about to bite at any unsuspecting moment when sitting in pew and force to listen to something I didn't have a clue about, nor had interest ! Always scared the Bejesus out of me as a 5 year old!
All the best and I hope this post was helpful.
Dennis
Mechanic