I'm replacing the engine ECM on my 93 LS400 with a remanufactured one I'm getting. Does the replacement ECM need to be reprogrammed for the car to run, or can I just plug it in and expect it to run? If anyone's replaced their ECM on a 93, I'd appreciate your input. I think the answer is no based on what I've read, but I've called a few parts departments who say it does need reprogramming.

Also for anyone who's curious what bad ECM symptoms look like, see: https://www.clublexus.com/forums/ls-...and-stall.html. My mechanic opened the ECM and found pretty obvious damage.

 

You don't need to reprogram it at all as long as you use a good same part #'s one.

 

Thank you! At the expense of sounding silly (since you say same part #), are 89661-50140 and -50141 interchangeable? My car came with a -50140 (93 LS production date 08/1992-01/1993), but the best unit I could find was a -50141 (01/1993-08/1993).

 

I don't know the detail but a 8966 -50141 has an improved firmware inside. I haven't tried to use it instead of a 8966 -50140 but the car should run.