GMC Heating & Cooling - Popular Questions, Answers, Tips & Manuals


It probably lost its 3/4 pack. That's the technical term meaning 3rd 4th gears are damaged due to the loss of fluid. My trans mechanic told me that there's a fluid port that supplies fluid to the 3-4 pack. And that port is designed too small, DESIGNED TO BREAK, after so many miles. That don't apply to your situation but if it will only go 20-30mph its probably not hitting 3rd gear. Time for a rebuild unfortunately. They can replace the 3-4 pack only but most shops will want to rebuild it in total. I found vids on the YouTube.

GMC 2001 Yukon... | 47 views | 1 helpful votes


Check fuse and relay, if good test pump.

GMC 2003 Envoy... | 485 views | 0 helpful votes


Easiest solution is to replace the fuse with a higher amp fuse.

But most advised solution is to first find out what the recommended size fuse is from the dealer and if it turns out you have the right fuse then there might be a short somewhere in the wiring.

So best get out your multi-meter and start checking your wiring.

GMC 2006 Envoy... | 33 views | 0 helpful votes


you cant jump an obdll to flash the numbers like in pre 1996 vehicles with obd ---go have truck canned most auto stores offer this service for free

GMC 2003 Envoy... | 37 views | 0 helpful votes


WHECH THE TOP OF THE DOOR OPEN,STICK A SINNING STICK AND PRESS UNLOCK BUTTON.

GMC 2002 Yukon... | 39 views | 0 helpful votes


Slim jim works all the time. This may sound nuts, but I proved it to work. If someone has a second key fob and a cell phone, have them click the unlock button several times really close to the phone. You get real close to the antenna and watch the doors unlock. This , of course works when you're stuck in a parking lot and the other key fob is miles away.

GMC 2002 Yukon... | 39 views | 0 helpful votes


Who checked it ? Was it the dealer or a qualified repair shop ? You need to know how it works to test the system . Pressing the A/C button enables the HVAC control module to request A/C compressor engagement and turn ON the A/C button LED. The HVAC control module sends a class 2 message to the PCM for A/C compressor engagement. The PCM will provide a ground for the A/C compressor relay enabling it to close its internal contacts to send battery voltage to the A/C compressor clutch coil. The A/C compressor diode will prevent a voltage spike, resulting from the collapse of the magnetic field of the coil, from entering the vehicle electrical system when the compressor is disengaged. Defrost and Defog mode selections will request A/C operation but not turn ON the A/C LED.
The following conditions must be met in order for the A/C compressor clutch to turn ON:
?€¢
Ambient air temperature above 1?°C (35?°F).


?€¢
A/C low pressure switch signal circuit is grounded.


?€¢
A/C refrigerant pressure sensor parameter is less than 2413 kPa (350 psi).


?€¢
A/C compressor temperature switch contacts are closed.


?€¢
PCM receives an A/C request from the HVAC control module.


?€¢
Engine coolant temperature (ECT) is less than 123?°C (253?°F).


This all happens if the PCM sees the right voltage from low & high pressure switches . Plus the fact that you say the compressor comes on when cold, then shuts off 5 min. down the road . Just off the top of my head I'd say you have a pressure switch problem. Possible
A/C Refrigerant Pressure Sensor The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5-volt reference, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0-5 volts. When the A/C refrigerant pressure is low, the signal value is near 0 volts. When the A/C refrigerant pressure is high, the signal value is near 5 volts. The PCM converts the voltage signal to a pressure value.
The A/C refrigerant pressure sensor protects the A/C system from operating when an excessively high pressure condition exists. The powertrain control module (PCM) disables the compressor clutch if the A/C pressure is more than 2413 kPa (350 psi). The clutch will be enabled after the pressure decreases to less than 1578 kPa (229 psi).
I would check it myself by finding the A/C compressor clutch relay in the under hood fuse / relay box an take a jumper wire an jump pin 87 & 30 sockets , where the relay plugs into the fuse box . If the clutch engages that part is good an there is a control problem ,not the compressor . If you pull the relay out of the fuse box an look on the bottom you should see four set of numbers , 87- 30 & 85 -86 .May have a fifth one 87a , don't worry about that one . There also be a diagram on the side of the relay . You can find videos on you tube testing relays . I would have it checked at another place too ,
I would

GMC 2003 Envoy... | 36 views | 0 helpful votes


Envoy cutting off - 2004 GMC Envoy - RepairPal

repairpal.com > Questions > GMC > Envoy > 2004 GMC Envoy
Sep 23, 2009 - My 2004 envoy has been cutting off ever since I replaced the battery. ...over beyond to the right and sometimes drops down way past the final. ... My enginecuts off when running air or heat what's the problem. 2003 GMC Envoy ... has recently started cutting off while in park and still on and while driving.

engine shuts down with defrost or A/C on : GMC Envoy ...

repairpal.com > Problems > GMC > Envoy
My 2004 GMC Envoy vibrates when I turn the air conditioner or heater on . It stallswhile I'm driving it and it ... 2003 GMC Envoy168,000Visitor. This solved my ... Truck will shut off while driving when I turn on A/C or heat. Also it will do the same ...

GMC Envoy shuts off while driving but starts up Questions ...

www.fixya.com > ... > Cars & Trucks > GMC
Ask your GMC shuts off while driving but starts up related question. ... after jump starting a car my 2003 envoy stalls out. dont know if computer needs ... shuts off while driving have to jiggle key sometimes to start The ignition switch is the most ...

2004 chevy trailblazer shuts off - CarGurus

GMC 2003 Envoy... | 495 views | 0 helpful votes


It's rare for G.M. to have such a problem like this one. If I keep it simple, common sense tells me you might have bad fuel or water in gas tank. Engine is missing causing retard spark and fuel, affecting traction sensor as well. This might cause the check engine light to come on too. Open hood and visually inspect for torn wires due to mice or rodents harboring in warm engine while you sleep.

GMC 2011 Yukon... | 102 views | 0 helpful votes


Mark, The remote I believe is as manual as it gets.

GMC 2003 Envoy... | 32 views | 0 helpful votes


Have you had a computer scan done. It is likely if a sensor or component is bad, the computer will tell you and save you the time of randomly replacing components. Low priced OBDII readers are readily available to home diagnosis. It would be a lot of things, crank position sensor, fuel pump could be bad, bad coil pack.

GMC 2002 Yukon... | 38 views | 0 helpful votes


This model shifter is released when brake peddle is pressed, it may need adjustment.

GMC 2002 Envoy... | 32 views | 0 helpful votes


Funny thing about car batteries, they will run the headlights and everything else but not enough current to run the starter. They fail just like you described, seems great one day, nothing the next. If you think the battery is good, try it in another vehicle by itself, not as a jump battery, by itself. If that test works perfectly you can go on troubleshooting the starting issue.

Starting issues can be anything from key detection circuitry, ECM issue preventing start voltage from getting to the starter solenoid, to the starter itself. Before going to all that trouble check all fuses under the dash and under the hood first, then go from there.

Not that you did this, but I am a strong advocate of not providing a jump to another vehicle from a working vehicle while your vehicle is running. The charging system can be damaged on your vehicle as you attempt to jump another vehicle. The alternator is only designed to recharge your battery based on the demand of your system and battery capacity, not to provide the type of current involved in jump starting another vehicle. If you must jump another vehicle, turn yours off completely and use your battery alone to provide the boost for the other vehicle. Battery failure can come from deterioration of the links between cells or at the cell grid attachment point and usually happen at the time of your last start, which is why they don't work the next time.

While I can't endorse a product, you could look into battery conditioners and see if they are worth trying, one of which is
Battery Equaliser Doubles Lead Acid Battery Life This is only for a new or relatively new batteries and won't do anything for a failed battery.

GMC 2007 Acadia... | 46 views | 0 helpful votes


to start with I would have the fault codes read by a professional as there will be a fault code recorded
next the noise can be from the incorrect oil filter used ( elcheapo filter)
Only use accredited service centers with experience on your make of car

GMC 2002 Envoy... | 47 views | 0 helpful votes


Transmission possibly. a friend had one with bad solenoids and caused similar problems. Throttle sensors may also cause this. Hope that helps

GMC 2003 Envoy... | 272 views | 0 helpful votes


the abs unit contains the pump so the unit that has all the brake pipes is the abs unit and the pump

GMC 2002 Envoy... | 59 views | 0 helpful votes


On a 2001 I don't think so. but disconnect the battery for a good bit and make sure everything as far as that goes battery is clean( terminals& cables ) ground is as important as power. shoud be fine after 1/2 hour.

GMC 2001 Yukon... | 66 views | 0 helpful votes


Your owners manual should show you location and amperage of the fuse for the cruise control. If no manual it should be able to be goggled for no charge.

GMC 2003 Envoy... | 55 views | 0 helpful votes


Car shuts off when A/C on - Discussion on Topix

www.topix.com > Chevrolet TrailBlazer
May 7, 2012 - 2002 Envoy SLE same problem. ... When it is at idle I can turn on the A/C and it will bog the engine to a point of stalling. When the compressor clutch engages the idle goes way down. ... i have a 2002 gmc envoy. when i turned my a/c on my vechile shuts down when i come to a stop, but as long im driving it ...

GMC 2003 Envoy... | 142 views | 0 helpful votes

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