raphman

Just a suggestion here, since it seems you've tried a lot already:

I had a very similar issue with my '05 C55 and did pretty much all you've mentioned. Car was in the shop for 6 months. The problem with mine, because Mercedes, was that the gas pedal module was intermittently sending a fault to the PCM, and thus provoking all the issues. Couldn't hurt to have it diagnosed by a shop and ruling that out. Best of luck.

Jasonoff

Wasn't there a specific fault code stored for that?

The unknown here are the generic Control Unit faults (5001, 5944, 5945) that's not associated to a specific sensor but the control unit itself.

raphman

You'd think there would be, but in my case there wasn't. All the shop kept seeing was the codes from the other items affected by the pedal fault. They replaced the ABS pump, ESP/ABS module, the entire wiring harness to the back and front PCMs, and some other stuff I can't recall. Eventually, the issue was found when, by accident, the mechanic saw a very minute and quick fluctuation in the voltage to the gas pedal.

Jasonoff

Weird. When I was troubleshooting, I data logged all the relevant sensors. Everything "looked" normal.

I was going to replace the module then it decided to stop faulting with zero intervention. Knock on wood has been fine ever since.

raphman

You're telling me... it was quite frustrating to no be able to drive the car I had purchase 3 weeks prior.

Good luck mang, hope it's resolved!

hyunman

Add another to the victim count. Just had this come on today. The error message seemed to come on at a certain speed.

Jasonoff - you seemed to be troubleshooting this the most - did you ever get it sorted out 100%? Did you end up swapping the module, and if you did, what did the dealer charge to code it to your car? My battery is pretty old and likely due for a swap so I'm going to get it tested and replaced tomorrow. I'll then try the lock to lock steering reset, and also clean the wheel speed sensors. BTW, the wheel speed sensors are the ABS sensors correct?

We'll see if these resolve the issue. If not, I may try to buy replacement sensors from the dealer and swap em tomorrow. I'll save swapping the module for the last step. $500 or so for the module itself seems doable - I just don't want to be charged twice that by the dealer just to code it to my vin..

Jasonoff

Depends what code the module is spitting out. If it's a specific sensor it's an easy fix.

If it's a control module code, it's something either in the module or a communication error.

I think in my latest case over a year ago, when it was control module error codes, it had to do with writing tunes. Something may have gotten into a error state loop.

I'm willing to guess more than half the the time replacing the module was unnecessary.

hyunman

Hey thanks Jasonoff. Going to pull the codes and see what it is. I have a tune on mine also so maybe that's it. Although it's been on there for half a year now and this is the first I've seen this happen. So you haven't swapped your module yet?

Jasonoff

Nope, it has been fine since it went on a fault spree last year, knock on wood...

hyunman

So I'm not seeing any codes. Used my torque app and had it scanned by two Autozones. Wonder if stored codes don't come up if I have the eurocharged tune on..

Disabled the auto lock before setting out. Also did the lock to lock steering reset someone mentioned. Drove about 30 miles since morning going to and from Autozones and no ABS errors yet. Battery test showed low charge. Considering the age of the battery, bought a new one. Will swap battery, clean off sensors and cross fingers...

Jasonoff

The EPS module stores codes. You have to access the specific module to retrieve them. It's not a DTC...

hyunman

Oh...
Well the cars been behaving all day..will see if it acts up again next week...

K3NnYDRuM

I drive an '09 C300 but I just had the same problem too with the ABS/EBR/ESP inoperative and power steering malfunction this morning. It occurred during a cold start driving about 300 feet from my house; however my power steering did not go out. Drove back home, ran my OBDII, no fault codes discovered. Restarted the car, let it run for a little bit, drove around the neighborhood doing some hard braking and turning, and the problem subsided for now. Gonna gas up as another test run. That ESP console replacement is a killer

Jasonoff

You scanned for generic DTC or scanned the module? Those errors will not log a generic ECU DTC.

AFAIW know, any ESP message up on the screen will be logged by the module. When I first scanned mine it had tons of stored faults.

Jasonoff

Mine started acting up again out of the blue. Generic control unit fault.

Was fine for nearly a year. May be time to just replace the POS...

EDIT: Star diagnostic scan appt with the dealer set for the 13th.

FEZZ00

just an update on this fault i had an no oem battery in my car it started causing all sorts of faults low voltage particularly, eventually went and brought the oem battery car has now has no faults esp unit 100% guys check your voltage it plays a critical role in the ensuring your control modules work

hyunman

Jasonoff-
How was your visit to the dealer? Is your issue resolved now? Could it be a new OEM battery like FEZZ00 said?

FEZZ00-
Has your error returned since swapping to an OEM battery?

My error just returned again on one of the days I need my car the most... I had cleaned the wheel speed sensors when I first saw this error. Also have a new battery but not OEM. And I also disabled the auto door lock. Error still came back out of nowhere. At work now so didn't have time to fiddle. I will try taking my EC tune off later today and go back to stock ECU as that seemed to make the error go away the last time I ran into this.

Jasonoff

They said the module was fried. It started working fine again a few weeks ago with zero intervention.

My battery is only a year old and I tried a deep cycle charge over night as part of my troubleshooting before going to the dealer to rule out the battery.

It's just a POS module in a bad location.

hyunman

Gotcha..did you end up replacing yours or are you just riding it out for now?

C SEXY 3

Haha this has been an ongoing thing for me for the last year. It's the ESP module unit and just gotta replace and code from with STAR.

Having my ESP module replaced today and BenzWorks is coding the unit for me today.

C SEXY 3

This is what happened to mine, it popped about a year ago so I got freaked. Then it started working fine with out me doing anything. Fast forward to today and it showed error again so I decided it is time to replace it. Bought the unit from dealer and it's so easy to replace do not have someone else do it. Just remove the old one, replace the seals, screw back on, drive without power steering to dealer, and have them code it for you. Shouldn't be more than $190.

Jasonoff

Did you already do that? I was told they need to read the data off the old one first in order to code the new one. Also told they can NOT re-code a used one.

Both could have been mis-information though.

hyunman

So I got back to my car and started her up. The errors lit up again like clockwork. I stopped by the house, reset my tire air pressure since my rears were off by about 2 psi for a week. Then reflashed my ecu to take the tune off and revert to oem ecu. Error went away...

Curious if the tune has anything to do with it. But doesn't explain why it ran well with the tune for the past few months. Of course, it could also be the resetting process that did it.

Anyway, I'm good for now. Maybe I'll get that module swapped. But what's there to say the replacement won't do the same..ugh

Jasonoff

I thought the tune flashing had something to do with it when it once worked for me. The tune does use more aggressive parameters but I think it's just a fluke because it didn't work for me this most recent episode.

I have yet to find anyone who knows how the module works.

For anyone who has replaced their old one and want to send it to me to open up I can share what's inside. Could be something obvious that's damaged etc...

C SEXY 3

It's getting done today, I do not believe they need to read the data from the old one. STAR didn't mention anything other then connecting to dealer network and registering it to the VIN.

I will call and ask Serge if that is the case, hopefully not since my mechanic removed the old one before driving it down lol.

I don't know about re-coding a used one I bought brand new from dealer.