PCM Swap

Shaners · January 27, 2004

Rather than keep repeating myself in the e-mails from many of you requesting instructions on installing the Wester's PCM, I figured i'd post it here for all to see!

Between the battery and the radiator you will see a black plastic housing. On the side toward the rear of the truck you will see a latch that I am pointing at. Insert a flat screwdriver under that latch and pry up. The cover will pop right off the latch and you just pivot it forward and up, and the front, lower latch will also release, freeing the cover. If you release the wire attached to the top first, you can completly remove the cover.

Here's what it looks like when you get the cover off.

See that metal clip about 2" to the right of my thumb? Pop it up off the PCM, then lift the plastic latch right next to my thumb. You can now tilt the PCM out and lift it partially out while tilting it so you can see and get at the connectors on the right side

Now you can get at the two 7MM (I think) screws holding the 2 connectors on. Loosen and unscrew the two screws untill the connectors are off. The screws will "jack" the connectors off. (They will also seat the connectors when you re-install.) When they are off, just lift the PCM out.

This is what the connectors look like, you can see the single screw in the center of each one. Make sure the orange silicone gasket you see here is in place on both connectors before you re-install the new PCM in reverse order.

Put it all back together, wash your hands, start it up and go for a ride. Don't baby it, Lyndon recommends flooring it a couple of times for the computer to learn your engine. If you get a little pinging on the first ride, don't worry about it. The computer will learn with-in anout 30 miles. Have the beer when you get back from the ride!

Butch 02 Sierra Denali

(Note: for pictures please visit Butch's guide at PCM swap )

sschevyz71 · January 30, 2004

thanks man!!!!!!!!!

bosssho · March 18, 2004

Hi, New to the board...so here is my first stupid question...what is the PCB and what are you getting out of changing it and what are you changing it to? Thanks!

Shaners · March 19, 2004

Hi, New to the board...so here is my first stupid question...what is the PCB and what are you getting out of changing it and what are you changing it to? Thanks!

The "PCM" is the power control module. It is the computer that checks and runs all the diagnostics on your engine/tranny. It controls shifting, fuel curve, timing, shift points and firmness and a whole bunch of other stuff.

By changing it to a custom PCM like a "Westers" you gain alot of performance and usually some added fuel economy!