I was wondering about this after the recent thread , I'm not trying to bring it back up but I was just wondering is there some sort of data somewhere that could register that something has been fiddle with/changed.

I've no experience with this so forgive me if I get it wrong, but eg if your ECU is flashed then down the road you want to return to stock so you put back on the original code would it be a case that information is missing from that period of time. You know the way that PC's register everything. I just thought that deep deep down would a good systems expert be able to find something not quite right.

I believe the ECU registers the change of map, and displays a value for the number of times it's been changed, If you know where to look for said value, it'd be pretty obvious.

They use a checksum. Some 'good' mappers would be able to aleviate this problem.

Certianly no dealer would be able to tell, but the factory may be able to. Thing t remember is the factory dont program the engine ECU so I think they would have to send it to either the manufacturer or a specialist.

I have seen ECU's and cars in at a tuning specialist being verified before now.

Yep, VAG have a procedure for this.

Cursory examination by a dealer probably will not reveal a previously held map - however if the ECU gets sent away they will find it. It was explained to me by Skoda technical exactly how they do this.......

It all depends on who or what it is reflashed to 'stock' with...

The ECU's have a flash counter so that will be different, if checksums don't add up (so to speak) then the car will most likely not work. There are also different versions of ECU numbers, VAG will update ECU's and the version # will differ.

In regards to our software we would flash in a stock binary file that matches the ECU in the car, so the version number will be the same. As for the flash counter, our software resets this to the last one anyway... no way of them seeing that anything's been done.

However, there is alot of other stuff out there that doesn't work the same way so back to my first line... it depends on who or what is being flashed in.

It all depends on who or what it is reflashed to 'stock' with...

The ECU's have a flash counter so that will be different' date=' if checksums don't add up (so to speak) then the car will most likely not work. There are also different versions of ECU numbers, VAG will update ECU's and the version # will differ.

In regards to our software we would flash in a stock binary file that matches the ECU in the car, so the version number will be the same. As for the flash counter, our software resets this to the last one anyway... no way of them seeing that anything's been done.

However, there is alot of other stuff out there that doesn't work the same way so back to my first line... it depends on who or what is being flashed in.[/quote']

Or in other words don't be fooled into buying a really cheap nasty remap and get it from the people who do it for a living and know what they are talking about.