So I recently added Weistec DP's and a stage 2 tune on my 2017 C43. I received my ECU back on Saturday. I plugged the ECU in, went for a test drive and everything seemed fine. Later that night while driving home, I received an error messages while on the freeway. The "Active Brake Assist Malfunction" warning popped up and my car lost all power. I was able to pull over, shut the car off and restart to get home. I am not sure if this is related to the tune or just a fluke. I have read this has happened before with a few members and simply needs a software update from MB.

I took the car in yesterday (AutoZone) to have it scanned since the CEL was still on. It is throwing the following 3 codes: P061B (Internal Control Module Torque Calculation Performance), and P0420/P0430 (Cat System Efficiency Bank 1 and 2.) I have read the P061B code has popped up post tune with a few guys on the forum due to receiving a bad file. I am confused by P0420/P0430 since I thought stage 2 would automatically disable/bypass the post-cat O2 sensors. Has anyone experienced this before?

Thanks in advance.

Possibly you were flashed with a stg1 vs. stg2!

They recommended I reset the throttle adaptations and clear the codes... Has anyone gotten the cat efficiency codes with stage 2? I didn't feel the "OMG THIS IS AWESOME" stage 2 power others have described so I am concerned they flashed stage 1 accidentally.

I got the same error message and a CEL with a EC tune. When they flashed it back to stock, it never happened again.

The Cat Efficiency code or ICM Torque Calculation Performance code? Did you stay stock or did they re-flash?

Mine threw the torque code - had it confirmed by a dealer in the area as well. I kept it at stock afterwards (we tried like 3-4 different versions of the tune and they were all throwing CELs and putting my car in limp mode at varying frequencies). The weird thing is that the tune was fine for 3-4 months and all of a sudden starting giving me issues.

Reading this is scaring me away from getting a tune. I've read that a few people are getting the CEL and going into limp mode after the Euro Charged tune. Has anyone had any problems with AMR or OE?

Which tuner do you have?

I had the same thing happen to me the day before yesterday. I was driving on highway at around 70 miles/hour. All at a sudden car just lost power with ESP light on and CEL.
I have stage 1 tune from. I did not know it was caused by tune when it happened, so I just sent my car to dealership... After it return I will probably flash back to stock and ask for refund. I don't want to risk my safety for the power gain...

It's almost as if MB sent a wireless update to all the cars... (not sure if that is even a thing). It's weird that no one had issues with their tune for months and then all of a sudden everyone is having the same issue....

Have any of you been in for service recently?

I visited the dealer one day before this happened. Not sure what they have done, but could be.

I did bring my car in for Service A while I still had my tune on it. I was under the impression that the dealer doesn't touch the ECU during service appointments unless they need to (updates aren't required). I had CEL issues with my car/tune well before that but I only got the active brake assist messages after that now that I think about it...

I had service A done 4 days before the tune.

Which tuning company did you use?

I am AMR stage 1 and have never had an issue ever! They also warranty the software and your motor, which is very comforting. That would be my tune recommendation hands down.

I agree 1000% ... I have AMR and no problems at all

My wife's C43 sedan had the Active Brake Assist Malfunction light come on a few weeks ago. Our car is NOT tuned. When I took it in to the dealership, they remarked that they had seen a few cars have this problem. They replaced something (can't remember what, since it seemed somewhat common, and was covered under warrantee) and sent us on our way. No problems since then. Possible not related to tune after all?

I had my car back from dealer. They replace the pressure sensor and some other parts. I will keep moniter. hopefully dont happen again. It is really scarry.

Did her car go into limp mode (i.e. no acceleration) when it happened? My car was constantly doing this and stopped when it was flashed back to stock.

Update about the situation.
I had the limp mode CEL, and sent my car back to dealership. Dealer replaced the pressure sensor and stated its fine now.
However, today,the day after I got my car back from dealer, on my way to work the issue occured again on highway.Now, I am turning to my tuner now...

Just go straight to AMR... they have it all figured out.. AMR told me they have the solution in there software and other tuners don't see the parameter that needs to be addressed because AMR has done extensive research in the tune itself

I second that^. AMR is literally the best company I have ever dealt with! Matthew is a pleasure to speak with and the engineering staff they have make a phenomenal upgrade. I would save the headache and just talk to them for sure

I third that lol

The Active Brake Assist Malfunction light came on when she was on the way to work. Since she was really close to the dealership when it happened, I just told her to drive straight there and I would call the SA. So since I was not driving, and she only drove a very short while after the light came on, I'm afraid I can't offer much help. I only mentioned because OP had listed that as one of the indications, and I wanted to let him know that indication happened without tune as well. I does seem strange, however, that so many of us get that fault starting a few weeks ago. Really makes you wonder if they can indeed "talk" to our cars.