What is the relearn procedure for a 2003 envoy? Envoy has smooth idle until a/c compressor comes on then it stumbles and cuts off. The battery cable was disconnected for about an hour. It has been about 2 weeks and it still has that problem.

The modules need to relearn the conditions it operates under. Take both battery cables off and touch them together for several minutes. Reconnect and start the engine. Drive the vehicle 20 or more miles in city traffic. That will relearn the modules.

try cleaning the throttle body with a good carb cleaner and tooth brush drive the car to relearn the idle if that don't work then try a pcm reflash

Try cleaning the throttle body first. Make sure to clean both the front side and rear side thoroughly. Also, disconnect the battery while doing the cleaning, this will reset the computer and allow it to relearn to the cleaned throttle body.
Unless you have the check engine light on and can retrieve a fault code, do not start to change parts. With the mileage you have, you may want to change the O2 sensors.

Alot of GM products you need to drive a little to reset the idle air control..If that dont help you may have a stuck idle air control which is located around the throttle body

I would get the alternator checked.

{: ) DTC P0506 Idle Speed Low
The usual cause is an excessive carbon build-up on the throttle body. If this is the case, I suggest you have your throttle body cleaned and perform an idle relearn procedure using a GM scan tool. The idle relearn or reset procedure is very important, otherwise this code may still remain even after a throttle body clean.
In a similar fashion, if the ECM/PCM (engine control module) of a high mileage vehicle is replaced and/or reprogrammed without performing the Throttle/Idle Learn procedure, the ECM/PCM may no longer compensate for existing carbon build up in the throttle body, causing it to return with a similar concern as well as DTCs P0121, P0506, and/or P0507.
There are other conditions that can also affect or reduce idle speed by increasing engine load like incorrect torque converter clutch (TCC) operation, accessories that require additional torque to operate, restricted exhaust, and mechanical conditions that limit engine speed.

WHEN EVER YOU DISCONNECT THE BATTERY.THE PCM WILL LOSE IT MEMORY PCM HAS TO RELEARN IDLE POSITION.SOME TIMES DRIVE AROUND BLOCK FEW TIMES CAR WILL RELEARN TO IDLE.IF NOT GO TO DEALERSHIP.THEY WILL RESET IDLE.USING A T ECH 2 SCANNER.THEY PROBABLY CHARGE YOU $35.00 OR LITTLE MORE.

please note that if your vehicle battery drain to less than five volts or battery disconnect without computer memory saver will set that code. first where your battery drain or disconected or the computer just throw that code , if battery where drain or disconected you will need to take your vehicle to a dealer and have them perform throttle relearn or a reputable shop with a compatible scan tool . if battery not aconcern check electronic throttle body for binding ,sticking foreign material ,carbon if any present cleaning or replace is recomend and relearn

There are a few things that you can do, do get it idling correctly, and it's fairly inexpensive.

1. Clean your throttle body with throttle body cleaner, with the battery disconnected. Needs to be shiny. When finished, drive around for 20 minutes or so with all accessories turned off, so the computer can relearn the newly cleaned TB. About $7 for the cleaner

2. Replace your spark plugs with A/C Delco 41-103, will idle better with this plug. Around $7 ea
3. Replace your upstream 02 sensor, the one right after the exhaust comes out of the engine, easy to replace. Between $67 and $80, try to stay away from Bosch.
4. Replace your fuel filter around $15 or less.
5. Check your vaccum lines for leaks.

Got a solution for you on this. There is a small sensor, called the MAP sensor.
It is located on the top of the engine. You will see a blue sticker with Delco Motors 5V GND written on it. Has a wiring harness that you can pry up and
pull off. Unplug the wiring harness and plug it back in. You may need to reset the code errors. I had mine at a mechanic, and he did that , reset the code errors and it solved the problem.