Restore Peak Performance to Your GM Truck or SUV
Is your 2004 GMC Sierra 2500, or another compatible GM vehicle, suffering from perplexing issues like a persistent check engine light, erratic shifting, poor fuel economy, or a no-start condition? The Powertrain Control Module (PCM), often called the engine computer, is the electronic brain responsible for managing your engine’s performance, emissions, and transmission functions. When it begins to fail, it can cause a cascade of frustrating and difficult-to-diagnose problems. This replacement PCM, part number 12586242, is the definitive solution to restore your vehicle’s factory performance and reliability.
From the Diagnostic Bay
We had a 2004 Sierra 2500 with the 6.0L V8 come into the shop with a complaint of intermittent stalling at stoplights and a check engine light that would come and go. The owner had already replaced the spark plugs, wires, and even the fuel pump with no success. Our scan tool pulled a P0606 code (Internal Control Module Processor Error). While this code can sometimes be a red herring, the intermittent nature of the stalling pointed towards an internal PCM failure. After verifying all power and ground connections to the module were solid, we installed a VIN-programmed PCM. The truck fired right up, idled smoothly, and the P0606 code was gone for good. The owner was thrilled to finally have his reliable workhorse back on the road.
Common Symptoms of a Failing 2004 Sierra 2500 PCM
A failing engine computer can manifest in numerous ways, often mimicking other component failures. If you’re experiencing several of the following issues, your PCM is a likely culprit. This module is a direct solution for these common problems.
- ✔ Check Engine Light is illuminated with codes related to module communication or processor errors (e.g., P0601, P0606).
- ✔ Your vehicle fails to start or starts intermittently.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ The engine runs rough, misfires, or stalls unexpectedly.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication issues with your OBDII scan tool.
- ✔ Seeming loss of power and sluggish acceleration.
The Critical Importance of VIN Programming
Simply installing a used PCM from another vehicle will not work. Modern vehicles use sophisticated anti-theft systems (like GM’s Passlock/Passkey) and require specific calibration files tailored to your vehicle’s exact options, engine, transmission, and emissions equipment. Our service eliminates the guesswork and the need for an expensive trip to the dealership. When you purchase from us, we flash the module with the latest GM-certified software updates using the Vehicle Identification Number (VIN) you provide. This ensures that the computer is a 100% plug-and-play solution, ready for installation right out of the box.
Guaranteed Compatibility
This Electronic Control Module is a direct replacement for service number 12586242 and is also interchangeable with a wide range of other service numbers, including: 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. It is designed to fit a large variety of 2004 GM models, such as:
- GMC Sierra 1500, 2500, 3500
- Chevrolet Silverado 1500, 2500, 3500
- Chevrolet Tahoe, Suburban, Avalanche
- GMC Yukon, Yukon XL, Sierra Denali
- Cadillac Escalade (ESV, EXT)
- Chevrolet SSR, Trailblazer EXT
- GMC Envoy (XL, XUV)
- Buick Rainier
- Hummer H2
- Isuzu Ascender
To ensure a perfect match, please verify that your original module carries one of the compatible service numbers listed above. Providing your VIN during checkout is mandatory for us to deliver a correctly programmed and fully functional unit.
Frequently Asked Questions
Do I need to do any programming or flashing after I receive this PCM?
No. This PCM arrives at your door fully programmed to your vehicle’s specific VIN with the latest GM software updates. It is a plug-and-play installation. In some cases, a security relearn or CASE relearn procedure may be necessary, which can be performed by a qualified technician.
Where is the PCM located on my 2004 GMC Sierra 2500?
On most 2004 GM full-size trucks like the Sierra, Silverado, and Suburban, the PCM is located in the engine bay on the driver’s side, under or next to the battery tray.
How do I provide my VIN number?
You can enter your 17-digit VIN in the notes section during checkout or reply to your order confirmation email. We cannot ship your part until we receive the VIN, as programming is a required step.
Will this fix my specific problem?
This module will correct any issues directly caused by a faulty PCM. While the symptoms listed above are common indicators of PCM failure, it is always best to have a proper diagnosis performed to rule out other potential causes like wiring issues or failed sensors.
What is a CASE relearn?
A CASE (Crankshaft Angle Sensor Error) relearn is a procedure that synchronizes the new PCM with the crankshaft position sensor. If not performed, you may get a P1336 trouble code. This procedure requires a high-level scan tool and is typically performed by a repair shop after installation.