This applies specifically to 03 and newer trucks, though I'm pretty sure they're all similar from 96~97.

This is for swapping the ECM, say... for a Wester's tune !!!! Very simple to do, takes maybe 10 minutes your first time, only tool needed is a 7mm nut-driver or ratchet.

Disconnecting the battery IS NOT necessary with our trucks, provided you do nothing foolish like spill your iced-tea onto the connectors or anything !!! Pull the ecm, put the new one right back in and you'll be fine

But if it makes you feel better, you won't hurt anything by pulling the battery, so do it


Pop the hood. Behind the driver's headlight will be a black plastic cover.



There is a length of wiring harness that runs across the cover, loosen it's clip and pull it aside. The cover has two catches, find them, pop them loose and remove the cover.



Here's the ECM !!

There are two catches holding the ECM. One is a metal spring clip, the other a plastic clip. Pop the metal one, hold it out of the way, lift the plastic clip beside it gently, lean the ECM out and it should lift up and out. The clips can be seen in the photo above.

With the ECM loose, tip is so you can get the wire bulkheads on the back. Each has a 7mm bolt holding it in place. Back each out and gently remove the wiring harness. Make sure the little rubber seals stay with the harness and not the ECM !! You can see the orange seal below:





That's it !!! Replacing the ECM is simply the opposite. Make sure your seals are in place and not kinked, be VERY gentle when pushing the harness bulkhead into the ECM, and make sure to not cross-thread the bolts !!!

Now, go fire it up and make sure everything's copasetic... and enjoy the ride !!!

Now, if it won't start ( ), see the write-up in this section, entitled Security Relearn.

Fear not, 30 minutes and you'll be running

This message has been edited. Last edited by: MrQuadrasteer,