2002 GMC Enovy V6, 4X4, 6 seater.

I understand we have to flash the emc. 1) is there an Android app? 2) how do we do it manually?

I'd rather not visit a dealer.

also the rear air ducts do not blow hot air, even tho switch is on for front to control and or rear control is set for heat. Front ducts blow heat excellent.

Flash the ECM? Why, where, how did you come to this conclusion?

And no, you can't do it with a phone or manually. Reprogramming must be done...wait for it... at the dealer.

While you are at the dealer, you might as well have them look at the rear heat system.

We researched why the gauges could be not working after replacement of battery and alternator. And it said reset computer. Which computer is ecm.. And flashing to my understanding is resetting. Second trying to avoid dealer cause we are on a set budget, being on disability, and dealer will want 70 plus dollars that we simply do not have after replacement of battery and alternator.

Now. We need a way to reset computer, or an app we can download. We already have a android code reader.

Thank you for your time.

I wonder if removing both battery cables for 15 minutes may re-set things.
* Before I can recommend the next statement, I would want to hear from our Gearheads about the safety of trying this on your 07.
* Also on some vehicles, removing both cables from battery, then touching both battery cables together for some time could do it?
Once again lets see what others say..

we have tried that. The disconnect for 15 min and re connect. Same issue with gauges. Did not have this issue before alternator and battery went bad. And its a 2002 gmc envoy slt v6. It will be 3-4 weeks before i can afford to take vechile to dealer. Hope to find reason why issue and get it fixed before then.

With the cables disconnected, did you take the disconnected cables and jumper them together for about 5 minutes?

Then with key out of the ignition, and NOTHING ON, attach positive cable first and then negative.....then start vehicle...

I don't see a problem with it. I had one I was doing that years ago that wouldn't act right. Disconnected both leads for a half hour at a time a few times. Car still acted weird. Touched both (disconnected) battery leads together. Still bad. Vice gripped both (disconnected) battery leads together for a half hour. Still bad. Vice gripped both (disconnected) battery leads together with a piece of #10 solid ground wire connected to earth ground for a half hour. Voila happy car (after is sputtered for a minute figuring itself out).

That was a '96 Buick. Earth ground was a 36" screwdriver jammed to the hilt in moist soil.

Did that fix it for super duper sure? I'm not sure. Maybe the number of resets did it. Or luck, or spirits, or . . . ? At the time I figured perhaps touching the battery leads together equalizes something, but connecting to Earth ground discharges it. And I was out of ideas.

CathedralCub, if you removed the tires, and let the car sit on rims, you wouldn't have had to do that!

That right ^ there is the best internet comment ever!

Which would be easier? :P

But while we're here, he'd only have to remove one tire for the same effect.

. . . then, I think about it more: Is there a good body-ground path to the outer edge of the rims? Wheel bearings have grease and rubber/poly/etc. seals. Steering arms have grease and rubber/poly/etc. boots. Struts same. Sway bars same minus grease. ABS cable as a path would have to pass through the wheel bearing. Perhaps through the brake line then the pad backing then the pad then the rotor? Not quite a copper-and-crimp path. It'* all academic but never thought of this before.

Then again, this would also depend on what kind of surface the rim is sitting on. Clean dry pavement is a poor ground path. Maybe the rim is sitting in mud?