I have a 99 5.3 and have been having alot of problems with my truck. I am looking to swap it for a 02 pcm to help remedy the problems. What all is going to be involved besides the swap. What else do i have to change? It will help the false knock and make the truck run better right? My brother has a 02 exactly like mine and the engine and transmission feel 100percent smoother and stronger than my truck.

 

do a search on here and i think you will find a bunch have done it.

 

I did a search right after i posted but have a few questions i didn't get. Do i HAVE to upgrade the injectors to swap the pcm. If so where is the best place to get some, i couldn't find any injectors in a search online. Also to get rid of the battery light do i just run a wire to the alt or did anyone ever make sure that fixed the problem. Also is there any need to retune the new pcm or can i just put in a stock 02 and run it as is. I would like a new tune but thats that much more money im going to have to pay all at once. Where are the cheapest pcms?

 

1)unless you progam the 02 pcm to use your smaller 99 injectors you'll have to get new ones. I used 24.5 lbs out of a 03.
2)The best place to get them is in the classifieds
I made sure, and don't for see any problems with it.

For pcm you get what you pay for, I have seen them for 200 on special.
I went with Nelson performance and don't regret it.
Theres been 10+ posts on pcms so happy reading.
I live in Ny were ls1edit dynotuning doesn't exist,


Heres what I posted before;
First off for the new guys I have a 02 Nelson Tuned pcm in my 99 Step side.
Bottom line without getting into it, I did this because it runs alot better than the 99 ever could.
The only problem I have is the flashing battery light and dtc code "Generator Terminal F circuit"
Looking at the wiring schematics between the 99 and 02 the only differance I found was an additional wire from the pcm Red terminal #52 to the alternator.
Terminal 52 is not used on the 99 pcm.

Well thanks to Allen I got a pcm clip and finally added the wire to terminal 52.
I ran it up to the alternator and now I'm only waiting for a new plug (02 plug on order) to plug in the alternator. The 99 doen't have a slot for it so I can't just add the wire to it.

If that doesn't cure it there may be a missing wire in the alternator itself. i tried taking the black plastic off the back but couldn't see if there was two wires or not. I ordered a GM 145a alt because I needed one anyway so that may have the upgraded wiring.
The next step after that is scaning the nelson pcm and picking up the vin and ordering a 02 bcm. the dealer is going to have to flash the new bcm with the vin from my 02 pcm.

Should know in the next few days when the plug comes in
I purchased an alternator clip from the dealer for an 02 alternator.
Part # 15306329 $14
It came with two wires coming out of it. I wired one to the stock 99 brown wire and the second to the new wire I had run from the pcm.Plugged it all in and No more flashing battery light


Sorry the update took so long i havn't had much time lately.


So it looks like for now to get rid of the light you have to run a wire from terminal 52 (red) to the terminal next to the factory wire on the alternator harness.

Thanks allen for the clip

 

I swapped for an 02 PCM too. Im gonna use Creeders method to get rid of the battery light flashing. But man oh man did my truck run better after I ditched the 99 PCM!!

 

Thanks i never had seen a post on whether the wire fixed the problem. So what i need is the alt plug for an o2 and a pcm plug to run the new wire and the 24lb injectors for a 02. For the pcm i was either going to get a stock 02 and run it if there was no problem and get hp tuners later. Would that be ok or am i going to have to have the 02 tuned with my vin before i can use it. If so i figure ill get a nelson and be done with it.

 

Yea, Creed figured out a fix for the flashing battery light. You can toss an 02 PCM right in there. But you will have to do the security re-learn and then you can start it up!. Security re-learn is outlined here

 

what do you guys mean by "the truck runs so much better" exactly ??.....

 

I had false knock problems from the get-go. So my truck ran like *** anyways. After I got my cam in it ran even worse. 8 degrees of KR all the time!!!!!! It ran horrid. I swapped PCM's and my truck ran perfect. For $60 bucks I aint complaining.

 

Any idea where I can find an 02 PCM for $60? Didn't see any on ebay.

Here's the most recent link with Creederado's success: https://ls1tech.com/forums/showthrea...23#post2002323