I own a 2008 E350 4Matic that has 76K miles and is in great condition. The last time it was at the dealer a couple months ago for the transmission fluid service, they did their usual multi-point inspection and came up with a whole list of recommended services. I ignored this, but then we had the “ABS/ESP Inoperative” error with power steering not functioning last week, so,I took it to a local shop that changed a front wheel sensor and fixed the issue. He also confirmed a few things on the dealer’s recommendations that we should address.

I took the car to a local indie that specializes in European cars and has a good reputation. He confirmed the same issues to be addressed (engine mounts had collapsed, needed new front axles, and all 4 brakes). He also said that there was an active code showing that the left front wheel sensor is inoperative. He printed out the diagnostics for me, and I see reference to the left front wheel sensor, and no reference to any other wheel sensor.

Sure enough, the ABS/ESP error with the stiff steering is back, so iI stopped off at the original shop that fixed the issue, and he ordered another sensor and I am going back tomorrow to get it fixed. The issue is that the receipt does not specify which front sensor he replaced originally, and he thinks it was the right side and I am now having the same issue with the left side. I have dealt with this shop,before, and found them to be honest, but I would obviously prefer not to pay for the same sensor twice.

So here are my questions: if it was the left sensor replaced earlier, is it likely that it went bad so soon (within a week)? If the left sensor is a new issue, why didn’t the second ABS/ESP inoperative issue come up sooner? The diagnostics showed the sensor issue, but the error message did not come up the second time until a couple days later. Finally, wouldn’t there be a stored error if the right wheel sensor ever had an error? Since the only reference to the wheel sensors is only for the left front, can I assume that this is the same one that the original repair shop replaced and that they are mistaken about having replaced the right side sensor?

Appreciate any insight as I know very little about these cars. For reference, here are the messages on the diagnostic report:

1425 Wheel speed signal,is implausible (stored)
D409 The left front wheel rpm signal from the traction system is unavailable on the CAN bus. (CAN timeout fault). (Stored (Event))

 

If the left wheel sensor is original to the car, you bet it will be obvious to tell if it had been changed recently. Keep in mind, sensors are not designed to last a lifetime, and it could be (bad luck perhaps) that both sensors died around the same time.

I have had issues with garages not being the most honest, but it takes a bite before I refrain to take my business elsewhere. I live by the thought that everyone is honest until proven otherwise. I avoid dealers mainly because of their outrageous rates, and not because of being dishonest in general.

 

One major reason we do our own work. "Never ascribe to malice that which is adequately explained by incompetence." - Unknown

 

Buy your own scan tool. For ~$150 you can do your own diagnostic work and avoid this type of hasel.

 

And you don't even need to spend $150. The Autel AP200 is about $56.40 right now. Scans all subsystems. As for the wheel speed sensor, some say the aftermarket ones aren't as good. The other issue is that the magnetic ring can also go bad but you will get a sensor error as the two go together. Too far in or too far out would also cause an error. The ring should MB only as there are also several reports of aftermarket parts not working right.

 

Thanks for all the responses. The good news is that I took the car back to the original repair shop this morning, and they fixed it. Never quite found out what the issue was, but they did not change the sensor, and they did not charge me again.

I wish I had the talent to do my own repair work; old age and lack of aptitude is not a good combination.