Computer Troubles

My friend's been having quite a bit of trouble with his Saturn (not sure of the model, but its a '98 or '99 sedan with the twin cam 4 banger) has been running like crap, won't stop right (abs issues), and gets horrible gas mileage. His mechanics say he needs a new main computer for it, since replacing the ABS controller, EGR valve, etc. didn't help any. They say that he has to take it to as dealership and have a computer programmed just for that car. Does he have to do that, or can he find another car with the same engine and transplant its computer? The car has just under 100k on it.

if you find an identical car will all the same you might not need to reprogram the computer. the PCM (main computer) should have NOTHING to do with the brake, plus a fault in the ABS system should NOT affect the standard hydraulic brake, try removing the ABS MASTER RELAY, if the braking problem is still there, look elsewhere. no offence to his mechcinic, but i think you should get a second diagnosis at another shop, even the dealership if possible. because PCMs rarely fail and sounds to me like he his replacing parts blindly because he can't find the root of problem.

I don't know what's gotten into our mechanic lately. It's like he WANTS to lose buisiness. He usually knows what he's talking about, but after this and what he did to my mom's car (looooong story), we're never going back.

I'll check that master relay. Do you know where it is? I'm pretty sure the car is an SC2. Can I just pull the ABS fuse?

the relay is located in the junction block under the hood