Mercedes dealership messing with ECU tune
Thread Starter
Newbie
Joined: Jul 2021
Posts: 1
Likes: 0
2016 C63s AMG Sedan
Mercedes dealership messing with ECU tune
I have a stage 2 tune that removes the CEL from the catless downpipes, but I had to take the car into the dealership to get some HVAC related stuff done. The only work I needed was to clean the evaporator and change out the filters, but they plugged the car in and said there was a software update that needed to be done. I told them no to the software update and even asked the SA again afterwards to make sure they didn't mess with my ECU. Lo and behold, a day later I got a CEL with the following codes
P2097 - Post catalyst fuel trim system too rich bank 1
P2196 - O2 sensor signal stuck rich bank 1 sensor 1
Car still runs as normal with the exception of the annoying CEL. Now I have to waste my time to get the car flashed again. Even though the work done was unrelated to the ECU they still messed around with it! Lesson learned, dealerships are absolute scum!
P2097 - Post catalyst fuel trim system too rich bank 1
P2196 - O2 sensor signal stuck rich bank 1 sensor 1
Car still runs as normal with the exception of the annoying CEL. Now I have to waste my time to get the car flashed again. Even though the work done was unrelated to the ECU they still messed around with it! Lesson learned, dealerships are absolute scum!
MBWorld Fanatic!
Joined: Nov 2004
Posts: 6,697
Likes: 382
2005 E55
I have a stage 2 tune that removes the CEL from the catless downpipes, but I had to take the car into the dealership to get some HVAC related stuff done. The only work I needed was to clean the evaporator and change out the filters, but they plugged the car in and said there was a software update that needed to be done. I told them no to the software update and even asked the SA again afterwards to make sure they didn't mess with my ECU. Lo and behold, a day later I got a CEL with the following codes
P2097 - Post catalyst fuel trim system too rich bank 1
P2196 - O2 sensor signal stuck rich bank 1 sensor 1
Car still runs as normal with the exception of the annoying CEL. Now I have to waste my time to get the car flashed again. Even though the work done was unrelated to the ECU they still messed around with it! Lesson learned, dealerships are absolute scum!
P2097 - Post catalyst fuel trim system too rich bank 1
P2196 - O2 sensor signal stuck rich bank 1 sensor 1
Car still runs as normal with the exception of the annoying CEL. Now I have to waste my time to get the car flashed again. Even though the work done was unrelated to the ECU they still messed around with it! Lesson learned, dealerships are absolute scum!
Super Member
Joined: Oct 2019
Posts: 841
Likes: 315
C43
Junior Member
Joined: Jun 2021
Posts: 65
Likes: 25
2018 C63 W205
If you don't have an "IN" with your dealer then yes they always check the ecu for the latest updates - This is mandatory if the car is still under warranty. PLUS the mechanic gets paid by Merc for flashing it. Therefore they are incentivized to check the ECU. If you got a CEL light then they reflashed the entire ECU and therefore your entire tune is gone.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
If you don't have an "IN" with your dealer then yes they always check the ecu for the latest updates - This is mandatory if the car is still under warranty. PLUS the mechanic gets paid by Merc for flashing it. Therefore they are incentivized to check the ECU. If you got a CEL light then they reflashed the entire ECU and therefore your entire tune is gone.
MBWorld Fanatic!
Joined: Oct 2007
Posts: 2,306
Likes: 381
From: Texas
10 C six trizzle
Not mandatory to make sure it's at the latest level, unless there is a campaign (recall or service bulletin) requiring it. In fact, there are specific instructions to not update modules without a cause, and they will not pay for it under warranty if there was not a valid reason to update the module.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
MBWorld Fanatic!
Joined: Nov 2004
Posts: 6,697
Likes: 382
2005 E55
Coming from my catless w204 c63 you do get the rich codes also. Just check to see if the monitor is turned back on with an obd scanner.
I would also think you would know if you were stock tuned 1 second of driving the car hitting boost lol.
My stock tune vs ptg stage 1 is like night and day. You just start laughing how fast the car is.. its like you added a new engine to the car.
I would also think you would know if you were stock tuned 1 second of driving the car hitting boost lol.
My stock tune vs ptg stage 1 is like night and day. You just start laughing how fast the car is.. its like you added a new engine to the car.
Last edited by skratch77; Aug 8, 2021 at 10:45 AM.
