Ah okay, so just getting my head around this. So the M52 unit is connect, flash and unplug while the DTUK unit remains fixed?
For tuning, you basically have 3 options:
Plug and play box - DTUK, Racechip, JB4 etc - they all have 3 sensors you connect which trick the car for more power
Plug in remap - Mountune, BSR, Bluefin - you remap/unmap the car yourself using OBD with a device they supply
Dealer - Revo, APR and other - dealer remaps your car and you have to take it back if you want to remove it
I think that's about right but might be corrected.
Sounds about right. REVO also offer both the "plug-in" option (SPS3) and a custom Dealer Map.
A word of warning though for cars inside VW warranty. There's lots of bollocks spouted from tuners claiming their maps/boxes cannot be detected, do not fall for it, everything is detectable by VW. Go into any tuning with your eyes totally wide open, and understand the risks involved. It's why I've been trying to do some research on the similarity of the components in the 245 v the R as I feel 310hp from a 245 is quite a jump and could put strain if they aren't capable of it. REVOSP3 is currently my first choice and I'll probably go with that, but I'm still trying to find out about the boost pressures and torque limits the 245 has.
Anyway, VAG cars have two flash 'counters'. The 1st is partially accessible by tuners, but the 2nd is completely inaccessible/encrypted and increments at every use of an external device which alters/changes the state of the ECU.
A VW dealership doesn't search for flags, they only look via ELSA for existing registered flags. Here in the UK, VW AG ask all dealers to run a specific diagnostic report (called SVM) which gets uploaded to the VW AG servers via VAS online. An automated response will be received and if a flag has been found, that flag will be shown and registered to the database. The diagnostic tool has no capability to do this locally. No information about a cars tuning state is held on the car's ROM, it's held centrally at VAG. VW keeps that record centrally of what the count number should be for each VIN (based on how many times it's been plugged into their systems), if the count displayed sits outside the number expected, then it goes into the first flash counter and looks for the TB1 and TD1 errors. When these are flagged, warranties are usually rendered void.
As mentioned, the flash counters serve two different purposes, one counts, one analyses. There is also another bit of the algorithm that analyses 'hardware' modification (tuning boxes and unidentified hardware that’s been plugged into the ECU) which produces a TXD code that is then monitored in the detection algorithm. It’s simple maths which will then flags the appropriate error (TD1, TG1, TE1 and TB1).
