2006 (5 cyl. 200K miles) H3 runs fine except that it stalls with no warning. Truck will driving fine (highway or local road) and suddenly the engine will shut off and I have to pull over. 30 seconds or so later it starts up fine and I continue to drive. Took it to Firestone and said that it was an ECM issue and that I have to take it to the dealer. Has anyone ordered one and replaced it yourself? I know places like Flagship One sell them (https://www.fs1inc.com/hummer-pcm-ec...8&p=2&year=139). You provide VIN and they ship them preprogramed. Just wondering if this is something I can do myself? I work on cars, basic tuneups, but never replaced electrical components. Any info/insight would be appreciated.

 

Welcome.

Have you scanned it with a scanner (not just a code reader)? Post the codes.
When was the last time you cleaned the MAF with MAF cleaner and the TB with TB cleaner? Read this >> Acts like it wants to stall/rough idle -No CEL -What To Do:

Are you still attempting to use the crappy azzed OEM Battery Terminal Connectors? If so, hack them off ASAP and replace with a quality aftermarket set like Stingers or your favorite brand. Can a PCM fail? Sure, but I would put that down the list of possibilities until I know a lot more about your issue.

If I were you and had to buy a replacement PCM, I would order one with a mail order tune from PCMofNC.com. They have plenty of info over there on the process and installation. Scale of 1-10, about a 2.

Stay AWAY from dealerships, your truck is long out of warranty.

 

I'd run lol!
seriously, start with common sense stuff.

Do the suggested items above.
Also, use oem products wherever possible. Stay away from shady aftermarket stuff (IMHO).
plugs, coils, crank sensor, battery cable ends, MAF, fuel pump, TB, etc. all are just as likely.
Get a real diagnostics done or do it yourself.

 

Don't run out and get another ECM.

Get it properly diagnosed, but ya, definitely make sure your battery, terminals, and alternator are all up to snuff.

 

Thanks for all the input (my first time posting). I got code P0601. I cleaned all electrical connections, replaced battery terminals (like you said the OEM ones are trash), new battery (old one was 5 yrs old), and problem still happened. Truck started fine, idled for about 5 minutes then shut off again. I bit the bullet and got an ECM from a local shop, ARES Technologies. I figured it was worth a try as they offer 30 day full refund and one year warranty. Sent them my VIN & $240 and the ECM was ready for pickup a day later. Removed old one and installed the new one in less than an hour and now the truck runs fine. Actually, it feels like it runs brand new again. So far so good.

 

Thanks for sharing your fix.