Is there any way to test the ECU without replacing it? My service manual calls for a tool called a test harness but I can't find one of these anywhere. I think there is a good chance the ECU has gone bad but want to be sure before trying to find another one. Thanks.

 

how do you know your ecu is bad or good?

 

I don't. It's just that I've gone through all the tests in the fuel and ignition sections of my manual. I've also checked the timing belt. It's getting fuel and spark. I'm stumped and the ECU seems like the only thing I haven't tested.