Buying an ECM and TCM
 

Is there any danger in buying these off of Ebay or from a salvage yard? I would like to have some tuning done but want to keep my stock setup since I'm under warranty. Just curious if I can hit the bone yard for them and save a few bucks.... Thoughts anyone?

Most mail order tuners can supply you with replacement ECM/PCM's for an additional cost.

I've probably bought about 100 used PCMs. I have only had 2 bad ones.So, In my opinion they are pretty safe to buy used.

Jeff

Yeah, I saw that. They charge a decent premium though, so I think I may go looking for my own.

Thanks Jeff. So, does GM use a basic PCM for a bunch of models or do I need to go searching for a specific part number? I'll do the searching, no worries, just curious how general I can be. My first foray into looking for one on Ebay shows the PCM working for a ludicrous amount of vehicles and I just want to have some knowledge up front. Oh, one more thing, and I'll apologize up front for the rookie type question, but what do these trucks have for modules? A PCM, ECM and TCM? For tuning I just need to pick up a PCM? Thanks again.

What year and model is your truck?

Sorry, I thought I had my signature set up. 2007 Yukon, bone stock, 5.3, 4 sp w/ 3.42's from what I can tell.

Edit to add, holy smokes 03Sierra, I just noticed your 1/4 time and your race weight. That's scary fast pushing 3 tons down the track.

2007 was the break point for which PCM was used. If it is the larger PCM with the 2-80 pin connectors then the correct PCM number would be a 12602801 PCM that controls the engine and trans. If it is the smaller PCM it would be a 12612384 ECM which only controls the engine. It can be difficult to get a different year Operating System into the "384" ECMs. That ECM was used for several years. If it is one of those it would be best to get one from an 07 with the same Operating System or have it initially flashed with a GM TechII if it is a "384" out of a different year truck.

Jeff

Thanks again Jeff. So if I understand correctly, I am hoping to have the larger PCM. If I find I have the smaller(384) version, I should look for one that came out of a MY2007 just to be safe. Plus, if it's a 384, I could only tune the engine and not the trans with that module. Interesting. Looks like it's time to locate it on my truck and see what I have. awesome help.

Correct. (To the best of my knowledge)

Jeff

You have the 2007 PCM so if the tuner is local make arrangements to have your stock tune installed if you need warranty work or if you are getting an autcal tune, you can do it yourself. Uploading tunes is a rather simple process, the first time you go slow because you are following direction otherwise is can be done in a few minutes. If you had a later model (I believe it was 2009+ or 2010+) then you should have the 2nd PCM to swap out.