lexdud

Late last year I was having issues with my car not idling unless you pressed on the gas. I solved the problem by replacing both the IACV and ECU. My car runs wonderfully ...

Fast forward to today. I recently purchased a spare ECU just in case I ever had ECU issues again. I disconnected my original, known good ECU and connected the spare. With the spare ECU the car runs very well except the TRAC light, indicating that the traction control system needs service comes on. If I hook up my original the light is off (there is no error). If I then reconnect the spare the TRAC light comes back on within 30 seconds.

My question is ... it appears to me that the second, spare ECU has an issue. Please chime in with your opinion. I would appreciate it.

Thank you ...

CrazySC300

iTrader: (16)

Maybe it's because that 2nd ECU was originally equipped on a car that didn't (or didn't) have traction control in it?

lexdud

Good point. It came from a 1992 SC400 and is the exact same model number as mine.

Didn't all SC400s have traction control? (since they are all automatics)

CrazySC300

iTrader: (16)

Whether it was a 300 or 400, Not all SC's came with traction control, regardless of it being automatic.

lexdud

Crazy, I accept your position but what about the model number on the ECU ... it is identical to the one currently installed in my car. If the ECUs are identical then why would the ECU be giving me a TRAC error?