Cant tune due to ECU lock
just purchased a mecerdes c250 w205 secondhand at 65kms
First merc, I'm absolutely loving it.
The vehicle had a racechip gts black which I have removed as I was planning to get a stage 2, have taken it to two different reputable tuners here in Brisbane QLD Australia, and they can read the ecu however can't write as they say its locked due to a possible prior tune. Did a bench read with same results
Spoken to the previous owner, he advised vehicle has never been tuned prior. Which given the racechip I erring on the side to believe him.
Both tuners said I have to take it to merc reflash the ecu to stock then take it to them for a tune so they can write on the ecu.
Rang mercedes, they said I have to buy a new ecu. Didn't say it was for a tune, just said I bought the vehicle and I want to reset the ecu. Sounds suss but I didn't know what wording to use as merc usually don't touch anything with a tune.
Question is, anyone experienced this problem before? Does this vehicle come with a locked ecu from the dealer? Is there anything I can do other than try and get mercedes to reset the ecu?
Car is running perfect, no dramas there.
The car came with this OBD2 device so unsure what this is
Came with car
Thanks to anyone that can help.
Will be posting more now that I have an actual mercedes in my garage not just a wallpaper on my phone
I dont think they come as locked as many guys are remapping without any issues.
Have a look bellow what AMG8 said makes sense to me:
https://mbworld.org/forums/c63-c63s-amg/707886-ecu-cannot-decrypted-tuned-help.html
Last edited by Andy74; Jul 3, 2021 at 05:05 PM.




I dont think they come as locked as many guys are remapping without any issues.
Have a look bellow what AMG8 said makes sense to me:
https://mbworld.org/forums/c63-c63s-...uned-help.html
thanks team.
much appreciated. Love the car, a pleasure to drive
sticking with mercedes all the way.
I still have the racechip, very hard to install on the w205 so I'll take it to the mechanic.
I had a look at the brabus powerbox, but hard to find here in the land down under. I was concerned initially with the racechip, but for what I want just a bit of extra kick, after some investigations seems reliable and safe, the stage two was to get some kick and get rid of the cel due to having an armytrix exhaust also. I got a spacer for this and its gone, so no dramas here.
Thanks heals for your help!
Last edited by AOMAS685; Jul 3, 2021 at 04:19 PM.
much appreciated. Love the car, a pleasure to drive
sticking with mercedes all the way.
I still have the racechip, very hard to install on the w205 so I'll take it to the mechanic.
I had a look at the brabus powerbox, but hard to find here in the land down under. I was concerned initially with the racechip, but for what I want just a bit of extra kick, after some investigations seems reliable and safe, the stage two was to get some kick and get rid of the cel due to having an armytrix exhaust also. I got a spacer for this and its gone, so no dramas here.
Thanks heals for your help!
much appreciated. Love the car, a pleasure to drive
sticking with mercedes all the way.
I still have the racechip, very hard to install on the w205 so I'll take it to the mechanic.
I had a look at the brabus powerbox, but hard to find here in the land down under. I was concerned initially with the racechip, but for what I want just a bit of extra kick, after some investigations seems reliable and safe, the stage two was to get some kick and get rid of the cel due to having an armytrix exhaust also. I got a spacer for this and its gone, so no dramas here.
Thanks heals for your help!



