Restore Peak Performance to Your 2004 GM Vehicle
Is your 2004 GMC Envoy XL, Chevy Trailblazer, or Silverado plagued by frustrating engine problems? An illuminated Check Engine Light, rough idling, stalling, or poor fuel economy are often tell-tale signs of a failing Powertrain Control Module (PCM). As the central computer of your vehicle, the PCM is responsible for managing everything from fuel injection and spark timing to transmission shifting. When it falters, the entire vehicle’s performance and reliability are compromised.
This is a direct replacement PCM, bearing service number 12586242, designed to resolve these issues and restore your vehicle to its factory specifications. We take the guesswork and high dealership costs out of the equation. Upon purchase, simply provide us with your vehicle’s VIN. Our technicians will then program the module with the latest, most stable software updates from GM, ensuring it is perfectly matched to your vehicle’s specific configuration. The module arrives at your door ready for a straightforward installation.
From the Diagnostic Bay
We had a 2004 Sierra 1500 with the 5.3L V8 come into the shop with a complaint that was driving the owner crazy. The truck would randomly stall at stoplights, but not always. Sometimes it would hesitate badly when accelerating. There were no consistent trouble codes, just a generic P0300 random misfire that would pop up occasionally. We checked fuel pressure, spark plugs, and coils—all were fine. After hours of chasing our tails, we monitored the live data from the PCM and noticed the ignition timing and fuel trim values were erratically jumping around. It was clear the processor inside the original PCM was failing. We installed a VIN-programmed module just like this one, performed a quick security relearn, and the truck ran like it just rolled off the assembly line. These intermittent issues are classic signs of a failing computer.
Is Your Vehicle Showing Signs of a Faulty PCM?
A failing engine computer can manifest in numerous ways. If you’re experiencing any of the following, a faulty PCM could be the culprit:
- ✔ Check Engine Light is on or flashing
- ✔ Vehicle refuses to start or is hard to start
- ✔ Rough or erratic engine idling
- ✔ Sudden stalling or cutting out while driving
- ✔ Noticeable decrease in fuel economy
- ✔ Harsh or incorrect automatic transmission shifting
- ✔ Failure to pass emissions testing
- ✔ Communication errors with diagnostic scan tools
Guaranteed Compatibility and Simple Installation
This module is a guaranteed fit for a wide range of 2004 GM trucks and SUVs. It replaces service numbers 12586242, 19299226, 89017738 and hardware IDs such as YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. It is the correct 2004 Envoy XL PCM and is also compatible with models like the GMC Sierra, Yukon, Chevy Silverado, Tahoe, Suburban, Avalanche, SSR, Cadillac Escalade, Hummer H2, Buick Rainier, and Isuzu Ascender equipped with compatible engines (typically 5.3L or 6.0L). Please verify your original part number to ensure a perfect match.
Installation is designed to be as simple as possible. In most cases, you will disconnect the battery, remove the old module, install the new one, and reconnect the battery. Depending on your vehicle’s security system, a simple key-cycle security relearn procedure may be required, which typically takes about 30 minutes and does not require special tools. We provide clear instructions to guide you through the process.
Frequently Asked Questions
Is this PCM really plug-and-play?
Almost! Because we program it to your specific VIN, it has all the correct software for your engine, transmission, and options. However, all GM vehicles of this era have an anti-theft system (Passlock/VATS) that needs to sync with the new PCM. This is done through a simple “security relearn procedure” that you can do yourself in your driveway with just the key. Instructions are included.
How do I find my service number on my original computer?
Your original service number is printed on the white sticker on the top of your PCM. It will be a prominent 8-digit number, such as 12586242. Matching this number is the best way to ensure compatibility.
What information do you need from me?
After you place your order, we will need your 17-digit Vehicle Identification Number (VIN). This allows us to load the exact correct GM-certified software for your vehicle’s specific build.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM also controls the transmission’s electronic functions, including shift points and line pressure. If your transmission issues are caused by faulty electronic commands from the PCM, this new module will resolve them. It will not fix internal mechanical failures within the transmission itself.
Do I need any special tools for installation?
No special tools are required. Basic hand tools like a socket set to disconnect the battery and unbolt the module are all that’s needed. The security relearn procedure only requires your vehicle’s ignition key.