California ECU vs. Federal ECU

I was just wondering, I have a 94 Geo tracker with California emissions and I believe my ECU is dead. It won’t start and I can’t get it to flash any error codes, I’ve checked spark, fuel, compression, and timing too. So I’m pricing out remanufactured ECUS and can easily find federal emissions, but not California. Is there a reason I cannot use a federal ECU with my car? would there be any potential problems with putting the federal emissions ECU into a California emissions car?

A look at AutoZone shows ECMs available in both Federal and California versions with the CA version being a 100ish bucks higher of course.

It’s a toss-up as to whether a Federal would work (at least tolerably) without problems or not. I haven’t pulled up wiring schematics to eyeball the differences and what would be affected but odds are something will be quirky.

There may also be equipment differences, items like smog pumps may be on a California spec car but not on a Federal.

There might be additional sensors or actuators on the CA engine, thus more “stuff” in the ECU.
If so the 49 state ECU might be jury rigged into your car, but it’s likely not a plug-and-play deal.

I just went through this with my daughters’ California emission car.

The difference with her car was it had a 3 way catalytic converter instead of the Federal 2 way catalytic converter, among other subtle differences.