My car runs great, but I have this code 3 stored in my ECU and it will not clear even after resetting it.

I checked for continuity between the ground terminals on the CAS connector and the negative battery terminal, and nothing.

Is something toast with my ECU? Can I ground those terminal's manually without frying anything?

I have not torn the ECU out yet to check for continuity between the CAS wiring harness (where it connects to the CAS) and the ECU terminals. That will be the next thing to try.

Anybody had this happen? What should I do if the continuity check between the ECU and the CAS connector is good (which I suspect it is).....assume the ECU is toast?

 

Check your ECU have you recently unplugged it or anything? make sure none of the pins have worked them self out when you plugged it back in.