Is Your 2004 GM Truck or SUV Running Poorly?
If your 2004 GMC Envoy, Chevy Silverado, Tahoe, or other compatible GM vehicle is experiencing frustrating issues like a persistent check engine light, rough idling, stalling, or poor fuel mileage, a failing Powertrain Control Module (PCM) is a very likely cause. The PCM is the central computer of your vehicle, responsible for managing engine performance, fuel delivery, ignition timing, and transmission shifting. When it begins to fail, it can cause a wide range of symptoms that are often misdiagnosed, leading to costly and unnecessary repairs of other components.
This replacement PCM, part number 12586242, is the definitive solution to restore your vehicle’s performance and reliability. We take the guesswork and hassle out of the repair process. Before shipping, we program the module with the latest GM-certified software updates specifically for your vehicle using the VIN you provide. This ensures a seamless installation and proper communication with all other modules on your truck or SUV.
From the Diagnostic Bay
I once had a 2004 Silverado 1500 come into the shop with a random misfire that the owner had been chasing for months. He had replaced the spark plugs, wires, and all eight ignition coils, but the problem persisted. A quick scan showed no communication with the PCM. After checking the wiring and connectors, we determined the module itself had an internal fault in the ignition control driver. Installing a pre-programmed 2004 GM PCM like this one solved the problem instantly. The customer was thrilled to finally have his truck running smoothly again after wasting so much time and money on other parts.
Key Symptoms of a Failing 2004 GM PCM
- ✔ Persistent Check Engine Light (CEL) illumination
- ✔ Engine misfiring, stumbling, or running rough
- ✔ Unexplained stalling or difficulty starting the engine
- ✔ A noticeable decrease in fuel economy
- ✔ Harsh or erratic automatic transmission shifting
- ✔ No communication with diagnostic scan tools
- ✔ False sensor error codes being stored
The Plug-and-Play Solution
Forget expensive dealership visits and programming fees. This module is designed to get you back on the road quickly. By providing us with your Vehicle Identification Number (VIN) during checkout, you receive a unit that is ready for installation. The only step required after you install the part is a simple security relearn procedure, which pairs the new PCM to your vehicle’s anti-theft system. This procedure can be performed by anyone in their driveway in about 30 minutes and does not require any special tools.
This module is a direct replacement for service numbers 12586242, 19299226, and 89017738, ensuring compatibility with a wide range of 2004 GM trucks and SUVs. Please verify the part number on your original module to ensure a perfect match. Restore the brain of your vehicle with a reliable, correctly programmed 2004 GM PCM and get it running like new again.
Frequently Asked Questions
Do I need to have this PCM programmed by a dealer?
No. We handle the programming for you before we ship the part. Simply provide your vehicle’s VIN at checkout, and we will flash the module with the latest GM software specific to your vehicle, making it ready for installation.
What is a security relearn procedure?
The security relearn, or anti-theft relearn, is a simple process that syncs the new PCM with your vehicle’s existing keys and security system. It typically involves a sequence of turning the key in the ignition and waiting for specific intervals. We provide easy-to-follow instructions for this process.
Where is the PCM located on my 2004 GM vehicle?
The location varies slightly by model. On most trucks and large SUVs like the Silverado, Sierra, and Tahoe, it is located on the driver’s side front fender, under the battery tray. On models like the Envoy, Trailblazer, and Rainier, it is typically found in the engine bay next to the air filter box.
How can I be sure this part will fit my vehicle?
This PCM fits a wide range of 2004 GM models. The best way to confirm compatibility is to match the service number on your current PCM to one of the numbers listed in our description (12586242, 19299226, 89017738, etc.). Our detailed fitment list also provides specific model and engine combinations.
What information do you need from me to program the module?
We only need your 17-digit Vehicle Identification Number (VIN). This allows us to access the correct factory calibration file from GM’s database to ensure perfect functionality for your vehicle’s specific options and systems.