Sloveniaboy

I've scoured the forums and have yet to find somebody who has encountered the exact same issue so I'm looking for any help at all, thanks!

The vehicle in question is a 2012 C250 4Matic Sport (Canadian 6 Cylinder)

This problem has happened about a few months ago and in the past few week has happened maybe 3-4 times so it is intermittent and doesn't happen every time I start the car. This issue leaves the car locked in park and not driveable.

When I unlock the car with my key fob, only one the passenger headlight and LED daytime running light work instead of both, this is how I know even before stepping into the car that the issue has presented itself again. Upon inserting the key, the steering wheel unlocks successfully but nothing works inside the car, no air, no radio, no seat control,windows, nothing. Starting the car works but I cant put the car in drive because nothing works within the interior, not even the brake switch to tell the vehicle it's fine to go into drive.

The engine starts successfully and runs but the engine fan immediately goes into high speed mode and I get these warnings on my gauge cluster.

ABS Inoperative
Run Flat Inoperative
SRS Malfunction
Cruise Control Inoperative

Two things have worked to resolve the issue and get me back on the road. One is just waiting, after a while of just sitting, the car will be back to normal and will function fine. Second is disconnecting the negative battery terminal and waiting approx 10-20 mins.

The last time this happened, the engine light remained on after the battery disconnect and the codes were

U0121
-Lost communication with Anti-Lock Brake System Control Module
P2158
- Vehicle Speed Sensor B

Once I cleared the codes, all was well and the engine light was gone. The car ran great and showed no signs of issues while driving.

This morning, same thing, unlock the car and only one headlight and daytime LED working (passenger side) and the same errors on the cluster, here we go again.

In my reading I've seen the following as potential culprits-

-Bad ABS Module (but how does this then explain all the interior electronics not functioning)
-Bad ABS Wheel Sensor (same as above, how does this explain all the other malfunctions and interior electronics not functioning)
-Bad Pre Power Fuse Box (I don't know much about this resolution but I've read it could be this)

Any help would be greatly appreciated!

Thanks

Sloveniaboy

Found this thread of a C300 with very similar symptoms, pm'd the owner, we'll see.....

https://mbworld.org/forums/c-class-w...lfunction.html

Hopefully somebody could shine more light on this issue.

Sloveniaboy

Fixed

At least so far, the issue was intermittent so time will only tell.

I replaced the prefuse box (sits directly in front of the battery in the engine bay) and all seems well.

Here is a pic for reference

the_indian_kid

how much was the repair bill, and in USD or CAD?

I think I'm leaning towards the same problem right now....

jackzhang

thank you, same here 2012 c300 4matic. solved the problems like you said second way, disconnecting battery for long time. I did one more thing is charging the battery when it disconnected.
you benefit every one.