I got my car tuned via the OBD port about three days ago. The car drives amazing, but I was alerted by a friend that my exhaust was sputtering at idle. I checked it out and sure enough it was. It makes a weird spitting sound at idling and the idle is very rough. Other than that, nothing is wrong. Later that day, I gave some friends a ride on the car to show the tune. I hit around 80mph on WOT almost and the CEL came on. A friend had a port scanner so he was able to find out the code P0108. I turned the car off and an hour later turned it back on to find the CEL off. I took the car to the tuner the next day (yesterday) and they were able to clear the codes and edit the idle enough to not have it sputter as much. I was told to drive the car for about a week and let it adapt to the tune. Later the same day I was driving the car aggressively and at about 70 mph on third gear the light came back on. I haven’t had any loss of power whatsoever and the car drives perfectly. The idle is rough however, that’s my only symptom apart from the CEL. I haven’t yet checked what code is causing the new light but I imagine the same P0108?

I have done the following modifications to the car prior to the tune, none of which have given me any problems:
- K&N drop in air filters
- Secondary cat delete

My car is a 2017 model year with about 22,000 miles. Let me know your thoughts guys. I’m not posting this to trash the tuner, in fact they’ve been very helpful and have given me some of the best customer service I’ve ever seen. But I wanted to hear your thoughts on what to do.

Thanks

Let me guess, this tune comes from EC?

One thing I will tell you from experience. Good customer support does not solve your tuning problem. Knowledge does. Which most of these run of the mill tuners do not have. These new Mercedes ECUs are extremely complex and they keep track of a plethora of different parameters. Most of the tuners get around this problem by shutting off most of these sensors which triggers other issues with the car.

To me it sounds like an ignition problem. May be one of the cylinder in misfiring.

If the tune gives you a problem from the get go, there is nothing to diagnose, cause why do you need to be guinea pig? Go back to stock. Return the tune. Choose a better tuner if you want a tune again.

EC? Is that a tuner? No mine is from elsewhere. I don’t want to throw names out now out of respect for the brand and the tuners helping me out. They’ve been great to me and I’m handling everything with them, so I don’t think it’s right to put this kind of publicity out for them. I’m just posting this to see if anyone else has had these problems of CEL coming on when you’re hauling ***, rough idle, and codes P0108 and P2A0D

I just saw the second part of your post. I agree completely. I was told to give it a week so the car adapts to the tune. But if it continues with these issues I have been thinking of taking it to Mo at DMETuning and do their tune

Heard good things about DME Tuning. Let us know how it goes.

I just noticed. EC = eurocharged right? Lol that took me a while, but no my car isn’t done by them. I wouldn’t touch them, Dime, or weistec from what I’ve heard

Both of the codes you're getting are for high voltage on the MAP sensors. They come back on because the ECU is seeing the high voltage on two consecutive engine start cycles. It almost sounds like they aren't plugged in all the way, or plugged in incorrectly. Did you disconnect ANY connectors when you installed the ECU upgrade, the drop-in filters, or did the cat delete? If so, recheck those connections. Also check the vacuum lines around the turbo and downpipe. Those are my first guesses as to the cause of the rough idle and the codes.

The tune could be the culprit, if the tuner doesn't know all the parameters that need to be set in terms of the ECU looking for voltage preset matching above a certain RPM (which would match what you are seeing because it's happening at high load). That needs to be turned off. However, given that you are getting a rough idle (it shouldn't be looking for the voltage match below 1500 rpm), I'm less inclined to think the tune is at fault, but rather an issue with the sensors, vacuum, or the connections.

Thanks. I don't think anything was disconnected for any of the modifications. I did the tune myself through the OBD port and the Dimsport handheld device and all I did was connect the battery to a stabilizer and hook the handheld up to the OBD port. The secondary cats I don't know because it was done at an exhaust shop here with a good reputation. The drop-in filters I didn't do myself- I dropped the screwdriver into the engine bay when installing it and took it to a mechanic to get the screwdriver out and he put the filters in for me. However I watched him do it and he just unscrewed the box and removed the plastic intake (which just clips on and off, I checked under the hood yesterday and everything looks fine).

Excuse my ignorance, but what do the vacuum lines look like?

I just got off the phone with the tuner who advised me to flash the car back to stock for the weekend and drive it as I have been to see if the CEL will come back on. If it does, it's an issue with the MAP sensor that would be replaced under warranty (they have a good relationship with a local MB dealership that they spoke with). If I understood correctly it also has something to do with the fact that my car has a bit more mileage (22k) so that could contribute to the MAP sensor going bad. They don't think anything is wrong with the tune because if it were, the car would throw the CEL but would also put it into limp mode. My car has never lost power.

What exactly is the P2A0D code? P0108 is an overboost code (coming from the MAP sensor as stated above), but P2A0D is a manufacturer-specific code that I can't find a description for.

I'm not quite sure either. It came up today, I did some research but all I found is that it doesn't reflect any mechanical issues but rather hints that something isn't to the ISO/SAE standard of operation.

Sorry for resurrecting a an older topic, but found out that the P2A0D code is a fault with the pressure sensors on the intercoolers. Good luck with it too because it's supposedly a ***** to get to.

Hello, did you solve that code only with changing the pressure sensor?

I too am having issues with these codes present. my car is fine on idle, but stuttering under acceleration at lower rpms, like its misfiring or stuttering, you can audibly hear it from the exhaust. My codes are same p0108 and p2a0d

I am having the intercooler map sensors replaced tomorrow and will update if that is the fix, i pray it is, if not i am not sure what else it could be. if it is the sensor in the intake manifold i will be sick to my stomach as that will be many hours to pay for in the shop. To put into perspective, just to have the two sensors replaced in the intercoolers is quoted from a independent shop $930 for 5.5 hours, that is not including the price of the sensors that i am bringing, just insane to me they engineered this engine not to be worked on easily at all.

Anyway, if anyone has any new info or if they too have replaced these sensor before please respond, others are having these same issues and codes and it will save others thousands in shop hours and unnecessary diagnosis fees

Thanks!