Difference Between California and Federal ECU

[Marc Boucher]

Just curious what the difference would be, vis-à-vis putting a federal ECU in a California car that is no longer owned or driven in California.

A month ago when I replaced my ECU modules, I could only finde a Federal unit at force5.  It works great, and I'm not in California so the CA emissions aren't so much a concern.

Two differences I can state between the CA vehicles themselves and the non-CA vehicles: 1990 I5's with CA emissions have both EGR valves and Cat converters.

Driving now with the non-CA ECU, the car drives great and everything appears fine.  In fact I no longer get that intermittent 'check engine light' which usually turned out to be code 
2411 (1989-91 Audi 100 only Exhaust Gas Recirculation Valve, (California Vehicles only) ). ...it would come on momentarily then go away.

Thus I'm curious if using the federal ECU means that its completely shut-down the EGR valve, or if its simply not monitoring any signals coming from the EGR.  

Thanks
MC