All wheel sensors are giving error codes, where do I start?

[Busterd814]

Hello all, I have a 2005 2500 Sprinter. Over the past month or two I have been having all kinds of problems with the ABS lights, traction control, etc. Dash warning lights come on then go off when I restart. then come on again. Wet weather makes it worse. I got it scanned at the dealer and all wheel sensors spit out codes, along with an improper ratio , which is a transmission shift error. I had replaced the drivers front sensor and drivers rear sensor recently. The codes I got were:

5477
549D
545B

and a CM improper ratio 2500

I'm thinking something electrical connection is a problem, but unsure where to start. Of course the dealer thinks something in the transmission is bad. If the warning lights kick on while I'm driving slow, the transmission has no issues. Transmission issues only happen when the warning lights trigger at highway speeds. Thanks for the help.

 

[autostaretx]

The first thing to look for/at is an oil leak at the transmission's electrical connection ...
... being wicked up to soak the transmission control module (TCM) that's under the driver's seat.
An all-too-common problem.

If you're lucky, fixing the leak (new seal) and really cleaning the TCM connectors may fix it.
If the fluid contaminates the inside of the TCM, it may require replacement.

--dick

 

[Nautamaran]

No experience with this personally, but when was your last transmission service? Was the conductor plate (shaft speed sensor) cleaned? It’s possible for metal dust to collect on the sensor magnet and cause the TCM to log an error, but that would be an output shaft speed.

I’m away from my desk so will leave the DTC interpretation and guidance to the more learned minds here, but having all four sensors go bad at once seems unlikely. I would expect an electrical fault such as a CAN bus comm error, worn wire insulation, or corrosion in a connector or ground somewhere. I had my ASR/ABS/ESP lamps flicker with no codes last year. It has remained in remission since I pulled and reseated Fuse Box #1 under the steering wheel and cleaned the grounds behind the dash hump and under the driver’s seat. No smoking gun found, but no flickering since...

-dave

 

[220629]

What Dick said.
Added: And Nautamaran. (Composing while he posted.)
+ 12 volt system voltage/connection problems (battery) and harness issues can trigger multiple and seemingly unrelated DTC's.

If you have a bunch of DTC's aka codes, it is sometimes difficult to sort them out. For a problem that I had, I created a chart which may help to put related DTC's together.

Module/DTC Record Chart T1N Module List
https://sprinter-source.com/forum/showthread.php?p=265288

If someone has cleared all of the historical DTC's without recording each and every one, the chart above will have less value/application.

vic

 

[Midwestdrifter]

It is important to know which module those codes were read from. Those codes would have been retrieved from the ABS/ESP module.

545B Right front wheel speed sensor value implausible

a. Inspect wiring.
b. The gap between sensor and rotor is too large or rotor is damaged or dirty.
c. Unshielded electromagnetic equipment may cause interference.
d. Wheel speed sensor defective.
e. Tires are mismatched or damaged.

549D
Incorrect wheel speed rotor at one of the wheels.
a. Tire pressure 1s Incorrect or tires mismatched or incorrectly fitted.
b. Tires may be damaged or out of balance.
c. The gap between sensor and rotor is too large or rotor is damaged or dirty.
d. Wheel speed sensors or wiring defective.


5477 Left rear wheel speed sensor (881) value implausible
...


Have you checked the rear axle for movement? The U bolts can come loose, and the locating pin shears. This causing the van to "crab walk" sideways down the road. Usually the steering wheel is a bit off center. Check the U bolts, and measure to see if the axle has migrated.

An implausible rear wheel speed signal will result in a "wrong ratio" code from the TCM. The TCM uses the rear wheel speeds to calculate the output shaft speed.

 

[Busterd814]

The transmission had a fluid and filter change along with the electrical connector seal back in February by a very knowledgeable service guy back in February when I was on a road trip. Long story about that episode, but kudos to the MB dealer in Oklahoma City. I will check the TCM under the seat along with the rear sensors. The left one I wired in myself, it may be loose. On a different note, I have driven the van across country without a front wheel sensor without issue, other than not having cruise control. So, if I can't track the problem, couldn't I just disconnect a wheel sensor? the van runs and shifts fine if the abs/traction lights are on from the start and stay on

 

[Nautamaran]

Check the gaps to the tone wheels while you’re back there.
You could disconnect, but eventually you’ll run out of sensors and lose speedometer and odometer inputs... and the ABS/ASR/ESP are safety systems you may wish you had some day.

-dave

 

[Midwestdrifter]

If you have a quality scanner, and you really should have one if own a sprinter and work on it. I would suggest monitoring the wheel speed sensors in real-time. That should quickly help you determine if the sensors are erratic.

 

[Busterd814]

Just wanted to ad an update. I checked the tcm connections for fluid. I did not see any obvious signs of fluid, however, there was a fair amount of dirt clinging to the harnesses like there had been some oil there. I cleaned that up, and the connections. I also rewired the left rear sensor that I had recently replaced. It didn't totally resolve the problem, however it seems like the error lights come on under more consistent circumstances. Now, I start it up, drive it down the road wet or dry and they stay off, that is until I come to a stop after driving for more than 5 miles. I come to a stop, start to pull away from the stop and then they come on. Speedo stays working and trans shifts fine, just no traction control/abs/cruise.
The right rear side of the axle has a fair amount of corrosion on the brake guard, I will probably check that sensor next, along with the right front.

 

[Midwestdrifter]

If it happens when coming to a stop, I would check the front wheel bearings for play, and the front tone rings for consistency.

 

[Busterd814]

I will check the bearings, but they are fairly new. I installed new ones 2 years ago. Are the tone rings part of the brake rotors? I live in the heart of the rust belt, maybe corrosion would effect the tone rings