Top 10 2002 GMC Envoy Questions & Answers

4.2L Engine the thermostat and the neck where the hose goes on is one unit $25 at autozone

1. Remove the necessary coolant from the radiator.
2. Remove the alternator, Loosen the outlet hose clamp at the thermostat housing. Remove the outlet hose from the thermostat housing.
3. Remove the thermostat housing bolts.
4. Remove the thermostat housing from the engine block.
5. Clean all of the surfaces of the thermostat housing.
6. Clean the sealing surface of the engine block.

if your outside temp is wrong on your 2002 Envoy here is how you fix it. part number 15047946 sensor. looks like the wrong part..it's not. take the brace part off of it by pressing the clips and slide out the part you need. Loosen the 4-5 bolts from the top of the grill..attached to brace right on top of the grill..just pull the grill out about 3 inches..put your hand thru..it's driver side to the middle. original is grey box with connector. pull it out, reattach connector to new part and push the new piece in the hole..get the piece from the dealer..25.00...put screws back in grill brace. reset the temp by pressing front defrost, rear defrost and mode all at once. took me 15 minutes..and I'm a 55 year old girl:) you can do it!

Might save you a whole lot of time if you stop by autozone, or Pep Boys, and get the free scan & see which sensor may be faulty, or sending code. I've had mine trip from driving in nasty weather for a while before, and a trip to the carwash, and concentrating the sensor areas with spray, (back of wheels area) put light back out, next start.

one, five, three, six, two, four

The plastic intake should have this sequence molded into it somewhere, and even the corresponding cylinder numbers in front of their respective holes. Have fun, and thanks for posting on Fixya.com

how to remove a bose cd/radio from dash of a GMC envoy slt cd's are stuck inside

P0440 - Evap system large leak. This code has a real common problem of the fuel fill cap either loose or the seal or check valve bad in the cap. There are also some hose and lines from the fuel tank to the charcoal canister that can be the problem. But most common is fuel cap loose or bad.

P0495 - Cooling fan rpm too high. This code sets when the control module has commanded the cooling fan rpm to zero and the rpm exceeds a predetermined amount. Your vehicle has a clutch driven cooling fan that the control module regulates through a solenoid valve. Most common problem is a stuck fan clutch which is consistant with the "jet plane" noise you are hearing. The clutch staying engaged when it should be slipping or "idling"
Good luck

The sift solenoids are located on the valve body inside the transmission.
The transmission pan has to be removed to gain access the the valve body. Once the pan is removed the valve body is in plain sight.
Removal of the transmission filter will grant you a clearer view as well.
This is a 4L60E transmission, in the event you have not purchased the solenoids.

Try pulling the rear hatch panel and move the unlock mechanism with a screw driver to get it to open.

If that does Not work:

Check for broken wires in the liftgate boot. Test the liftgate module powers and ground on the 4 terminal connector: 12 volts on the Orange wires in terminals A and C, ground on the Black wire in terminal D. The liftgate module is located inside the gate.

you need to replace the tccm and get it programmed.


2-04-21-006E: Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System, DTC C0550 Set No Communication with TCCM (Reprogram Transfer Case Control Module) - (Jul 20, 2006)
Subject: Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System, DTC C0550 Set, No Communication with TCCM (Reprogram Transfer Case Control Module) Models: 2004 Buick Rainier 2002-2004 Chevrolet TrailBlazer, TrailBlazer EXT 2003-2004 Chevrolet Avalanche, Silverado, Suburban, Tahoe 2002-2004 GMC Envoy, Envoy XL 2003-2004 GMC Sierra, Yukon, Yukon XL 2004 GMC Envoy XUV 2002-2004 Oldsmobile Bravada with Electronic Shift or Active Transfer Case (RPOs NP1, NP4 or NP8)

This bulletin is being revised to add Subject information and change the labor operation. This bulletin cancels and supersedes Bulletin Number 03-04-21-006. Please discard Corporate Bulletin Numbers 02-04-21-006D and 03-04-21-006 (Section 04 -- Driveline/Axle).
ConditionSome customers may comment that the 4WD/AWD indicator lights on the selector switch do not work, or the 4WD/AWD system may be inoperative and/or the service 4WD light is illuminated. The condition is typically intermittent and always occurs at key-up. Upon investigation, the technician may find DTC C0550 set.
CauseThe Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode".
When the TCCM is in the "sleep mode", it will not communicate with the class II bus or the Tech 2®.
Correction

1. Try to communicate with the TCCM. If no communication, go to step 2. If communication is possible, go to step 5.
2. Remove the underhood (ATCM or TREC) TCCM fuse.
3. Wait 30 seconds.
4. Reinstall the fuse. The module should "wake up" and communicate with the Tech 2®.
5. Check for codes in the TCCM. If a C0550 is found current or in history with or without other codes, replace the module and go to step 6.
6. Reprogram the TCCM with the latest TIS software using normal SPS procedures.
7. Verify operation and that no codes are present.

Important: For the 2002 model year, the TCCM must be replaced and reprogrammed.
Warranty Information

The trans shift cable is held onto the shifter with a little round plastic clip that you can get from the "help" section at your local auto parts store for under $15. Common problem, the clip wears out and the cable pops off.