I'm not really qualified here (and if someone is please post) but I've been poking around with the ECU on my 2001 audi and it doesn't seem to have ECC memory either. A section of the AM29F800BB eeprom is used as random-access memory. It seems to stick a couple CRC bits in every line so maybe this is how they're doing it?

I am starting to think that safety critical systems need to have schematics, pcb layouts, design documents and source code be registered with the gov before it touches the public.

I remember when nearly everything came with schematics so it could be fixed.