[f5fstop]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TA8088:
Thanks fstop!! Using the part # you supplied I was able to find them at GMPartsDirect for about $28 each. I was told that I would need to have the sensors programed for me so that they work. I was also told that the spare has one and that I could pull that one so that I only have to buy three. </div></BLOCKQUOTE>

I'll save you some money, and offer a bit of advice.
First, I would purchase all four, since if you have to use the spare, and it has no sensor, you will get a TPM message, that is up to you though.
However, no need for a dealer to program, you can do the learn procedure supplied in the owner's manual. That is all the dealer will do. It takes a dealer a less time since they can use the TPM tool, but why pay them a minimum of one-hour work, if you can do the same thing in about fifteen or twenty minutes.
The TPM tool just activates the sensors to produce a low frequency transmission that the BCM learns.
In the owner's manual procedure, it tells you to inflate or deflate a tire, this is causing the sensor to sense a change in air pressure, thus signalling the BCM, and then the BCM learns the sensor.
So, doing it yourself might save $50-70.00.

TPM Sensor Learning
Each TPMS sensor has a unique identification code. Any time you rotate your vehicle's tires, install the spare tire onto your vehicle, or replace one or more of the TPMS sensors, the identification codes will need to be matched to the new tire/wheel position. The sensors are matched to the tire/wheel positions in the following order: driver's side front tire, passenger's side front tire, passenger's side rear tire, and driver's side rear tire.

You will have one minute to match the first tire/wheel position, and five minutes overall to match all four tire/wheel positions. If it takes longer than one minute, to match the first tire and wheel, or more than five minutes to match all four tire and wheel positions the matching process stops and you will need to start over.

The TPMS sensor matching procedure is outlined below:

Set the parking brake.
Turn the ignition switch to ON with the engine off.
Turn the exterior lamp switch from AUTO to ON four times within three seconds. A double horn chirp will sound and the TPMS low tire warning light will begin to flash. The double horn chirp and flashing TPMS warning light indicates the TPM matching process has started. The TPMS warning light should continue flashing throughout the matching procedure. The SERV TPM message will be displayed on the Driver Information Center (DIC).
Start with the driver's side front tire.
Remove the valve cap from the valve cap stem. Activate the TPMS sensor by increasing or decreasing the tire's air pressure for 10 seconds, then stop and listen for a single horn chirp. The single horn chirp should sound within 15 seconds, confirming that the sensor identification code has been matched to this tire and wheel position. If you do not hear the confirming single horn chirp, you will need to start over with step number one. To let air-pressure out of a tire you can use the pointed end of the valve cap, a pencil-style air pressure gage, or a key.
Proceed to the passenger's side front tire, and repeat the procedure in Step 5.
Proceed to the passenger's side rear tire, and repeat the procedure in Step 5.
Proceed to the driver's side rear tire, and repeat the procedure in Step 5.
After hearing the confirming horn chirp for the left rear tire, check to see if the TPMS warning light is still flashing. If it is, turn the ignition switch to LOCK. If the TPMS warning light is not flashing, the five minute time limit has passed and you will need to start the process over beginning with Step 1.
Set all four tires to the recommended air pressure level as indicated on the Tire and Loading Information label.
Put the valve caps back on the valve stems.