How many different ECU firmware versions are there?
 

I've been looking all over for information that could tell me how many different ECU firmware versions there might be in total across all 96-98 993's.

I'm involved in a research project on OBD2 that could potentially benefit a lot of 993'ers with SAI-related emissions problems.

The workaround I stumbled upon is legal, toatlly free, easy and non-invasive. I was able to pass my 97 C2S with known SAI faults this past July using this technique.

The problem is I don't know if it worked on my '97 because my ECU firmware is "unique" in some way or if most or all 993's could be expected to behave the same way. A firmware version/VIN lookup table would be best, but lacking that, even any info as to how many versions there were (one for each year, 10 , 20, 50??) would be useful.

Any help is much appreciated.

Thanks, Jay