Is your 2004 Hummer H2 running rough, stalling unexpectedly, or displaying a persistent Check Engine Light? These are classic signs of a failing Powertrain Control Module (PCM), the electronic brain of your vehicle. A faulty PCM can disrupt everything from engine timing and fuel delivery to transmission shifting, leaving you with an unreliable and frustrating driving experience. This replacement PCM, part number 12586242, is the definitive solution to restore your vehicle’s performance, reliability, and efficiency.
We take the guesswork and hassle out of the repair process. Unlike sourcing a module from a junkyard or a dealership, our PCM comes pre-programmed specifically for your truck. Simply provide us with your vehicle’s VIN (Vehicle Identification Number) after purchase, and our technicians will flash the module with the latest, most up-to-date software directly from GM. This ensures perfect compatibility and function right out of the box, eliminating the need for an expensive trip to the dealer for programming.
From the Diagnostic Bay
We had a 2004 Sierra with the 6.0L come in that was driving the owner crazy. He had replaced the throttle body, MAF sensor, and all eight spark plugs chasing an intermittent stalling issue and a P0606 code (PCM Processor Fault). The truck would run fine for days, then suddenly die at a stoplight. After confirming all sensor inputs were good, we focused on the PCM itself. We swapped in one of our VIN-programmed 12586242 modules, performed the quick security relearn, and the truck ran perfectly. The customer called back a month later, thrilled that his truck was finally reliable again. It’s a powerful reminder that sometimes the issue isn’t a sensor, but the computer reading it.
Solving Your 2004 Hummer H2 PCM Problems
A failing engine computer can manifest in numerous ways, often mimicking other component failures. If you’re experiencing any of the following issues, a faulty PCM is a likely culprit. This module is engineered to resolve these exact problems and get your vehicle back to factory-spec operation.
Common Symptoms of a Failing PCM
- ✔ Check Engine Light: The module may trigger various diagnostic trouble codes (DTCs), especially communication or processor-related codes.
- ✔ Engine Stalling or Misfiring: Inconsistent signals can cause the engine to stumble, misfire, or stall completely, often without warning.
- ✔ Poor Fuel Economy: Incorrect fuel mixture and ignition timing calculations will lead to a noticeable decrease in MPG.
- ✔ Harsh or Erratic Shifting: The PCM controls the transmission, and a faulty unit can cause delayed, hard, or incorrect gear changes.
- ✔ No-Start Condition: In severe cases, the PCM may fail to activate the fuel pump or ignition system, preventing the engine from starting at all.
- ✔ Failure to Communicate: Your OBDII scan tool may be unable to connect with the vehicle’s computer system.
Guaranteed Compatibility and Simple Installation
This PCM, identified by hardware number 12586242, is a direct replacement for a wide range of GM trucks and SUVs from the 2004 model year. It is compatible with multiple service numbers, including 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. Whether you’re driving a Hummer H2, GMC Sierra, Chevy Silverado, Tahoe, Suburban, Escalade, or another vehicle on the list, this is the correct component to restore your engine’s command center. The module is typically located in the engine bay on the driver’s side, under the battery tray, making access straightforward. After installing the new module, a simple security relearn procedure (often called a CASE relearn) may be necessary to sync the new computer with your vehicle’s anti-theft system and crankshaft position sensor. This procedure can typically be done without special tools and instructions are widely available.
Frequently Asked Questions
Do I need to get this computer programmed by a dealer?
No. We handle all the programming before we ship the part to you. Simply provide your vehicle’s VIN during or after checkout, and we will flash the module with the correct GM software for your specific vehicle. It will be ready to install upon arrival.
What is a CASE relearn and is it required?
A Crankshaft Position System Variation (CASE) relearn is a procedure that allows the new PCM to learn the specific characteristics of your engine’s crankshaft position sensor. It is often required after PCM replacement to ensure accurate misfire detection and engine timing. This procedure can usually be performed with a capable bi-directional scan tool or sometimes via a specific drive cycle.
Where is the PCM located on my 2004 Hummer H2?
On the 2004 Hummer H2, as well as most compatible GM trucks like the Silverado and Sierra, the PCM is located in the engine compartment on the driver’s side, mounted underneath the battery tray.
Is this part compatible with other GM vehicles?
Yes, this PCM is compatible with a wide range of 2004 GM trucks and SUVs equipped with 5.3L and 6.0L engines, including the Chevy Silverado, Tahoe, Suburban, Avalanche, SSR, Trailblazer EXT; GMC Sierra, Yukon; Cadillac Escalade; Buick Rainier; and Isuzu Ascender. Always verify your original part number or service ID to ensure a perfect match.
How do I provide my VIN for programming?
You can add your VIN in the notes section during checkout or reply to your order confirmation email with the information. We cannot ship your part until we have the VIN to program it correctly.