Hey guys, sorry if this has been covered before but I need to know if a remap is visible with the dealers diagnostics systems.

I was told by one Skoda dealership that the remap would present itself as a series of error codes on the diagnostics, where as another said that it was pretty much invisible unless it was compared side by side with a standard ECU. A Vauxhall dealer also said to me that it is easy enough to find if the car has been mapped but normal diagnostics don't delve that deep.

Apart from the dealer guessing by looking at the flash count of the ECU, who is right? My car is going in for warranty work in a couple of days and I need to know whether to put the standard map back in or not.

Any help would be much appreciated!!

Cheers!

It wouldn't show up in a fault scan and it wouldn't be immediately obvious. But a test drive with some datalogging or ECU data comparison would show it up immediately.

I'd put it back to standard if I were you just to be on the safe side.

Remaps are not "undetectable" and don't let anyone tell you any different!

Some tuners alter the control module identification, others don't. Flash counters can be reset, but even a counter set back to zero may be questionable if the car for example had a factory/dealer reflash. As shark already explained data logging and comparing checksums may be better indicators, a good dealer tech usually has a feeling for such things - hard evidence on the other hand is another thing.

Doesn't the ECU also record the flash tool last used? If it doesn't tie up with the proper VAS tools (if used) surely it would look suspicious.

It also depends on what the warranty work is for.

The ECU keeps a counter of how many times it's been flashed, although some tuners rewrite that. This doesn't make the remap invisible, a simple look at such params like turbo boost, and the feedback from various sensors will show different values than stock, tipping off a well trained tech.