Get Your Truck Running Right Again
Is your 2004 GM truck or SUV suddenly running rough, refusing to start, or throwing a persistent check engine light? A failing Powertrain Control Module (PCM) can bring your vehicle to a dead stop, causing frustrating and unpredictable issues that disrupt your work day and your peace of mind. This professionally programmed engine computer is the definitive solution to get you back on the road quickly and reliably. It arrives ready for installation, flashed with the latest GM software updates specifically for your vehicle’s VIN.
Common Symptoms & Your Solution
A faulty PCM can manifest in numerous ways, often mimicking other sensor failures. If you’re experiencing any of the following, a failing engine computer is a likely culprit:
- Persistent Check Engine Light (CEL) with communication error codes (like P0601, P0605, P0606).
- Engine stalling, sputtering, or misfiring.
- Harsh or erratic automatic transmission shifting.
- A complete no-start condition where the engine cranks but won’t fire.
- Reduced fuel economy and poor overall engine performance.
Instead of wrestling with a used module from a salvage yard that requires expensive dealer programming, this unit provides a direct, effective fix. We handle the programming for you, making the replacement process as straightforward as possible. This is the smart, reliable way to restore your vehicle’s factory performance and dependability. When you order your 2004 Sierra 2500 PCM 12586243, you’re not just buying a part; you’re buying a solution.
Features & Benefits
- ✔ VIN-Specific Programming: Arrives pre-flashed to your vehicle’s exact VIN, ensuring compatibility and eliminating the need for a trip to the dealership.
- ✔ Plug-and-Play Installation: Once installed, your vehicle will start and run, though a security/CASE relearn may be necessary depending on your model.
- ✔ Updated GM Software: Programmed with the newest OEM software updates from General Motors to correct known factory bugs and improve performance.
- ✔ Restored Performance & Efficiency: A properly functioning PCM is critical for optimal engine power, smooth shifting, and factory-spec fuel economy.
- ✔ Broad Compatibility: This module, part number 12586243, fits a wide range of 2004 GM trucks, vans, and SUVs.
- ✔ Peace of Mind: This unit is backed by our one-year replacement warranty.
From the Technician’s Bench
“Over my 20 years in the shop, I’ve seen countless drivers chase expensive sensor and component replacements only to find the root cause was the PCM all along. A common mistake is buying a used module without realizing it won’t work until it’s programmed to the vehicle. That programming can cost hundreds at a dealer. Our process solves that problem. By flashing the 2004 Sierra 2500 PCM 12586243 with the latest GM software and your VIN *before* we ship, we provide a part that’s ready to get your vehicle back to its reliable, hardworking self.”- Veteran ASE Certified Technician
Frequently Asked Questions
How do I provide my vehicle’s VIN?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot program and ship your module without it. You can find your VIN on your vehicle’s registration, insurance card, or on the driver’s side dashboard visible through the windshield.
Will I need to do anything else after installation?
In many cases, the vehicle will start and run immediately. However, some GM vehicles require a security relearn procedure (often called Passlock or VATS) and a Crankshaft Variation Relearn (CASE). These are simple procedures that can often be done without special tools, or by any qualified mechanic.
Is this the correct part for my vehicle?
This module fits a wide range of 2004 GM models. Please review the detailed fitment list on this page and match the part number 12586243 or 89017739 to your original unit. If you are unsure, please contact us with your VIN before ordering and we will be happy to verify compatibility.
What does “programmed” mean?
Programming, or “flashing,” is the process of loading the correct vehicle-specific software onto the module. This software controls everything from fuel injection and spark timing to transmission shifting. Without the correct program for your VIN, the module will not function in your vehicle.
Why is this better than a junkyard part?
A part from a salvage yard will be programmed for the vehicle it came from, not yours. It would require costly and time-consuming programming at a dealership. Our module is cleaned, inspected, and programmed with the latest software for your specific VIN, providing a more reliable and convenient solution.