Wrong ECM

[Fless]

It may not have the correct calibration for your truck, and you may need to go through the security relearn. Good luck with it; curious to know how it goes.

 

[Tonyrodz]

So, I found an ECU from an '04 Suburban with the 5.3l. It has the same part number as what I "think" my Tahoe is supposed to have, 12586242. Hopefully, other than having the wrong VIN, it will clear up some of the wierd stuff going on, so I can focus on what really needs my attention. I'll try to remember to come back and close the loop on this after I get it. If

It would need to be completely flashed to your vin.

 

[George B]

Why not order a replacement flashed for your truck already. There are several online vendors that provide such a service.

 

[George B]

Example: https://www.fs1inc.com/2004-chevrol...omputer-pcm-ecm-ecu-programmed-plug-play.html

 

[Mudsport96]

You will probably have to do the antitheft relearn to get the vehicle to start since the computer wont be matched to the vehicle. Easy to do though

Gm key relearn

 

[Twithers]

So I put in the ECM I got online from the '04 Suburban with a 5.3l. I did the 3 cycles of 15 minutes with the key on. The truck started right up the next time. I let it idle for about 15 minutes. Since the ECM came from a different vehicle with all it's own learned info, I disconnected the battery for 15 minutes. Reconnected the battery and took it for a test drive. So far I've found that just the change of ECM corrected all of the throttle problems, passing gears, speedometer accuracy, fuek range calculation and a couple others I can't think of at the moment.

Thanks for the help.