I had weird pcm problems even have extra pcm due to ordering new one thing to fix problem. FIX WAS TO GROUND PCM TO FIREWALL PULL PCM FROM PLASTIC MOUNT WRAP BARE WIRE AROUND THRU HOLE IN PCM THEM PUSH IT BACK IN TO HOUSING THEN CONNECT BARE WIRE UNDER NEAREST BOLT unscrew bolt wrap and tightn bolt grounding pcm let my truck shift right and reduced power went away. They have a ground for the pcm through transmission and when tiny wire breaks you need to change everything to fix. Or you just ground pcm itself to firewall. This is ether mega stupid or sinister considering one wire or $6000.00 in repairs. 2007 hummer h3 3.7 i5 Removed air box, external trans cooler no connection to radiator, new wire grounded PCM, greased front hub bearings through ABS sensor holes. She runs like the wind still learning to read tech 2 it is really helpful with hummer h3 bugs. To the tune of Reana S & M Hummer may be bad but Im perfectly good with that..........

 

Hi Guys, I’m back and unfortunately not with good news. After I put the new battery in it ran for a while but has since gone back into low power mode. Given the advice from here I changed the terminal connections and that worked for about 100 miles.

As a recap this started about 8 months ago or so. When it originally happened, I changed the throttle body and gas pedal, then I had it “flashed” by the dealer. Ran great for about 6-7 months and then it came back. I’m pulling a combination of P2135, P060E, and P2138; however, P2135 is by far the most common and sometimes is the only code pulled. I changed the battery and the terminals. But alas I am still pulling those codes resulting in low power mode. I’m officially at a loss.

PS I used all OEM parts except the battery terminals which are solid lead.

Thanks for for all your help guys!

 

Did you check the tb connector? Wd40/electrical contact cleaner/electric grease etc...

 

You talking about the Auto Parts el cheapo lead terminal connectors? The ones that have to bolts through a plate that hold the cable to the terminal....

 

Yes sir - similar to the above. I needed something to keep the truck going in the temporary while I research which quality ones to get. (I’m looking at stinger SPT55302, but hesitant as I’m not running anything extra from the battery and do not need the extra connections). Anyhow, the cheap terminal connectors should still be working in the short term as they were only on for about a day and about 150 miles. I understand it’s temporary but why would they fail so quick?

 

Clamp terminals are not recommended ever. I have found numerous customers driveability issues in the past caused by those terminals. Most were bottomed out on the terminal and the wires were still loose.
Stingers use the same concept of the ac circuit breakers inside the fuse panel in your home, a bolt pressing against the stripped portion of the wire. Properly tighten the bolt, and you will NEVER lose connection.


The H3 has 3 positive leads and 2 negative leads routed to the battery terminals, get some stingers and separate those leads so they are all independent and make sure to properly clean/lube/tighten all leads.
Stingers are costly, and worth every penny!

I still have the spt53502 terminals and never had a problem since installing them.


https://stingerelectronics.com/catal...ducts/spt53502

 

Thanks Hummerz much appreciated. This is probably a stupid question but given that on the negative side there’s only 2 leads you don’t need to do anything special? Just install the two leads and leave the other connection empty?

 

Yes, or you can install another ground wire. Just make sure the wires you install are clean and bolts secured tight.
Clamp and crimp connections, are weak, especially when there are 3 wires crimped together, outside in the elements, corrosion sets in and causes a connection loss in between them.
I like the spt53502 design, as it covers the battery terminals too.

 

Just had the cold weather limp mode happen again this winter only when temps hit 20’s or less. Cleaned MAF and replaced pedal. No fix. Went to dealer....they ended up finding no connection issues and finally replacing Intake throttle body/sensor . Hope it’s the fix...wierd issue only in 20F.

Also had them install the new lock cylinder for the 10 min wait intermittent issue and the recall HVAC wiring.


First major issue in 89,000 miles 2009 Lux.

 

Yes, temp inside auto repair shops are not @20°F, and most techs refuse to test in the elements. I can see you lost a lot of money throwing parts at it, however when the issue returns, come back and ask for advice. GL