EDIT Think I found the problem. After taking a closer look at the ECU board I found a leaking capacitor and a scorch mark.
thanks
t
Hey
I have a similar problem. I have a 91 Mirage sedan with the F4A21 auto in it. The tranny is stuck in limp mode. I pulled the TCU out and it has this number MD#739458. Having a hard time finding another used to check and see if this is the problem or if its something else. A friend told me it might be the solenoids. Going to order a pack and install those next.
I have pulled out the TCU and cracked it open. [s]All the caps and traces look fine. It actually looks brand new inside, very clean.[/s]
Anyone have a cross reference for TCU swaps or know which will work for me?
Thanks
T