Dealer system destroying remapped ECU's

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Lee44

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Oct 29, 2014
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C250 CDi AMG Sport
Hi guys, I just want to put this out there as it's concerning for many if there's any truth in it.

I've a 1yr old GLC 250d, which has had a bench remap. The dealer informed me this week it needs a recall for Audio20 and light software updates.

In the meantime I've been catching up with and old friend who happens to be an indie specialist. He stated that now once the new Dealer systems are plugged into your (newish) Merc for any software upgrades, and it detects any anomalies in the ECU like a remap, then it will send a signal back and destroy the ECU, making it unusable. Thus a new ECU needed at around £1500.

Now I've heard of Dealer software upgrades just wiping over the remap, resulting in you just having to return to the guy who installed it and having it re done. But I've not heard of this new news where it destroys the ECU.

Has anyone any steer on this? Is there any truth in it? It's quite concerning if so.

Thanks
 
If you remapped a 1 year old car you have invalidated the warranty.
 
I wouldnt have thought it would “destroy” the ecu as that would be damaging another persons property which last time i heard was a criminal offence
 
If you remapped a 1 year old car you have invalidated the warranty.
Only if the map could have caused a component to fail.

If a door fell off for example your warranty would still be valid.
 
I wouldnt have thought it would “destroy” the ecu as that would be damaging another persons property which last time i heard was a criminal offence
That was exactly my first thoughts on the matter.
The Dealer don't own the car. It's mine.
 
Newer models will indeed have their ecu's interrogated and if found to be non-original then the system will overwrite with the official software.
This is to ensure the car still complied with any and all emission controls present at type approval.

The ECUs will not be destroyed, as posted above this would be criminal damage?
 
Perhaps this is a half-truth. - They over-write the ECU with the default settings, and if that bricks it they will contend it's your fault, not theirs, for fiddling with it in the first place.

There is no reason for the ECU to be damaged by being reset, unless part of the involves something that has been removed. - I don't know if it's plausible, but for example if it expects to be able to operate the EGR and that has been removed, then it's going to throw errors.
 
Thanks for that, reinforces my initial thoughts.

Is the Technician likely to spot the remap on their systems or will they have to go searching for it? I wonder if the Dealer is likely to "have words" with you about it if found?
 
The diagnosis system will find any remap, despite what the remap seller will tell you.
Generally speaking though the dealer won't routinely scan the system as this take time, so unless there's a good reason, say an official update to apply or the customer has reported some issue, nothing will be done or said.
 
Definitely no EGR removal like some companies offer. Just a custom bench remap as far as I'm aware.

I was told initialy that the ECU's were a nightmare to remap and a lot couldn't achieve it because of the new encrypted software in them.

If I'm being totally honest it hasn't made a huge amount of diffrrence performance wise. And some days question if it was a placebo and done at all. I still have a few GLC 220d chomping at my heels. Even a A200 the other week!?

Maybe I've just got used to the the power.. Anyway that's another topic.
 
It's going in for the recall Audio20 and upgrade on some lighting issue and passenger airbag warning light been on since new.

Best case scenario it will just wipe over it.
 
Many remappers will rewrite the map FOC, or very small charge, should it get wiped.
 
My only concern was how new this news maybe, if it's pretty recent then not many would know about it.

I'm sure there will be guru's on here or techs that would know for certain if it's new news or some real truth in the concern.

Thanks so far guys
 
I suppose the concern is heightened by the fact it's a bench remap rather than a OBD remap.

Although I am not exactly familiar with the differences other than they open up the ECU to do their stuff, rather than a plug in way. It's what actually happens once they open it up and begin their remap work. I wonder if there is soldering or moving wires etc on the board?

This might be the issue where it is more easily found by the Dealer systems.
 
Opening the ECU is almost certainly a warranty forfeit, for systems issues anyway. OBD port written maps are no different from the updates done by the dealership. All changes set flags and checksum counts change.
Bench remaps usually involve removing the ECU chip to access the various pins for rewriting code. There will obviously be physical evidence of the work as well as software flags.
None of which should be an issue generally but clearly MB are likely to be less sympathetic should problems arise.

Did the remap make much of a difference to the driving experience? Do MB offer a plug-in box (used to be from Brabus) that wouldn't trouble the warranty?
 
Hmmm that's interesting!

Well.. Driving experience wise If I'm being totally honest it hasn't made a huge amount of difference performance wise. And some days question if it was a placebo and done at all. I still have a few GLC 220d chomping at my heels. Even a A200 the other week!?

Surely they all couldn't of been remapped too !!

I'm unsure about plug ins due to the new encrypted software in these ECU's
 
The diagnosis system will find any remap, despite what the remap seller will tell you.
Generally speaking though the dealer won't routinely scan the system as this take time, so unless there's a good reason, say an official update to apply or the customer has reported some issue, nothing will be done or said.
I don't think the dealer needs to scan the system, I believe there is a software flag that indicates remapped ECU's.
 
I would have thought that:

1. They are unlikely to voluntarily apply a software update to any module that does not have a recall and that the owner did not ask for.

2. In the event that they do apply a software update to the engine ECU, it will simply remove the old map and won't do any harm.

3. If they somehow brick the ECU, they will treat it as a warranty repair, even if you have remapped the ECU, because you did not ask them to update the software in the first instance.
 
On another note... on one hand owners can do what they like to their cars, and invalidate the warranty if they so wish.

On the other hand, where I do see a potential issue for MB, is in relation to IPR, because remappers make changes to software code copyrighted to MB, and potentially sell it on - but I don't know for fact what is the legal position on this, or if MB are actively going after remappers - I suspect not.
 

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