ok,we are wanting to get our pcm retuned,for all of those who did it,what exactly had to happen,i know i have to send it in,but my question is,when i get it back,can i do everything right there at home,or do i need to take it to a dealer,there isnt a hummer dealer around here except for kansas city,and that is 3-4 hrs away.this is something that is a must as i am wanting to add bigger tires,and that poor little 3.5 really could use a little bit more,all help would be great

 

Well it depends on which option you use. If you go with a loaner, it is one of the easiest modifications you could ever make to any vehicle, right in your own driveway. If you would search "PCM" or PCMforless, you will have volumes of reading to answer your question. https://www.hummerforums.com/m_18248/tm.htmfrom HummerGuy, and better yet, https://www.hummerforums.com/m_21150/tm.htmfrom kelly@pcmforless. PM Kelly if you have further questions.

 

Hilljob, I just did it a few weeks ago. 1) Order the loaner option. 2) Remove original PCM, install loaner, do security relearn. 3) Ship off original, get it back within a week. 4) Put original back in, return loaner. 5) Smile with the improvements and performance gains! And read the other threads about the details that I'm glossing over. Once you figure out how the PCM is latched in, it's just a few minutes of work at each change. No dealer involved, no downtime. [/align]

 

what about thatCASE thing.some guys are saying they had to go to the dealer to have that fixed,what exactly do they fix and what do they fix it with,some kind of scanner,it has to do w/ the crankshaft sensor,only im not sure if it bothers anything

 

If you do the loanerprogram there is no CASE (Crankshaft Angle Sensor Error)relearn! The only time that is necessary is if you do the Core Exchange. If you get that error you have the dealer do a rescan, actual scan time isvery short, but depends on how busy and cooperative your dealer is.

The loaner program is very easy. See alrock's quikee over view above. Piece of cake.

 

i gotcha now,i thought even w/ the loaner one you still had to have that done,much easier now.thanx

 

Anyone post MPG after PCM upgrade? Better or worse? I'm sure worse until your foot comes off the pedal after the newness wears off.

I would be interested to know if MPG improves. Not that it's important.....

 

The consensus seems to be 0 improvement for a very few (enjoying a boost in power and heavy with the foot) up to some reporting 3mpg improvement?? Still, if you increase the drivability of the 3, and can improve mileage by 1-2mpg. No brainer. Everyone agrees that it takes a couple of tanks of gas to see all the improvement because of two things: 1) getting your foot out of it like you astutely observed; 2) PCM learning after the tune, takes at least 500 miles or so.

 

i am still trying to save up for mine,so hopefully soon