Restore Peak Performance and Drivability
Is your truck or SUV feeling sluggish, unpredictable, or just not right? A failing Engine Control Module (ECM), or Powertrain Control Module (PCM), is often the hidden culprit behind a host of frustrating issues. This genuine GM control module, service number 12586242, is the definitive solution to get your vehicle back on the road with the reliability and performance you depend on. Forget the guesswork and the endless cycle of repairs. This is the brain of your vehicle, and we provide a perfectly matched, plug-and-play solution, giving you the confidence of a job done right.
Signs Your Engine Computer Needs Attention
A faulty PCM can manifest in ways that are easy to misdiagnose. If you’re experiencing any of the following, it’s time to consider the source. Replacing your module can bring back the smooth, responsive drive you’ve been missing.
- ✔ Check Engine Light: Persistent illumination, especially with communication-related codes like P0601 or P0606.
- ✔ Poor Fuel Economy: An inefficient engine burns more gas. A new PCM restores precise fuel and timing control.
- ✔ Engine Stalling or Misfiring: Erratic signals can cause intermittent stalling, rough idling, or misfires that seem to have no other cause.
- ✔ Transmission Issues: Harsh or incorrect shifting can be a direct result of bad data from the PCM.
- ✔ No-Start Condition: The most critical failure—if the brain isn’t working, the engine won’t start, even with a good battery and starter.
An Expert’s Note: The Diagnostic Dead End
“I once worked on a 2004 Tahoe that had its owner completely stumped. He’d replaced sensors, checked wiring, and was about to give up on a random, intermittent stalling issue that no scanner could pinpoint in the act. The problem was a hairline crack on the PCM’s circuit board that would separate when it got hot. Swapping in a properly programmed module didn’t just fix the stall—it gave him back the dependable family vehicle he trusted. It’s a reminder that sometimes the most complex problems have a straightforward solution.”
Effortless Steps for a Confident Installation
We make this repair as simple as possible. By programming the module to your vehicle’s unique Vehicle Identification Number (VIN) before it ships, we handle the most complex part. You’re left with a simple physical swap.
- Safety First: Begin by disconnecting the negative terminal on your vehicle’s battery to prevent any electrical shorts.
- Locate the Old Module: On most of these trucks and SUVs, the PCM is located in the engine bay, often on the driver’s side near the battery or airbox.
- Disconnect and Remove: Carefully unplug the color-coded wiring harness connectors. They have locking tabs that need to be released. Once disconnected, unbolt the module from its mounting bracket.
- Install the New PCM: Mount your new, pre-programmed 2004 Sierra 2500 PCM in place and securely fasten the bolts. Reconnect the wiring harnesses, ensuring each plug clicks firmly into place.
- Reconnect and Start: Reattach the negative battery terminal. Your vehicle is now ready to start. Note that a security or CASE relearn procedure may be required with a capable scan tool for full functionality.
Guaranteed Compatibility for Your GM Vehicle
This module is a direct-fit replacement for a wide range of 2004 General Motors vehicles. Please verify your original part has one of the following service numbers to ensure a perfect match: 12586242, 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, or YHTN.
This part is confirmed to fit the following 2004 models:
- Buick Rainier 5.3L
- Cadillac Escalade, ESV, EXT
- Chevrolet Avalanche 1500
- Chevrolet Silverado 1500, 2500, 3500 (Gasoline)
- Chevrolet SSR
- Chevrolet Suburban 1500, 2500
- Chevrolet Tahoe
- Chevrolet Trailblazer EXT 5.3L
- GMC Envoy XL, XUV 5.3L
- GMC Sierra 1500, 2500, 3500 (Gasoline)
- GMC Sierra Denali
- GMC Yukon, XL 1500, XL 2500
- Hummer H2
- Isuzu Ascender 5.3L
By purchasing this 2004 Sierra 2500 PCM, you’re not just buying a part; you’re investing in peace of mind and the renewed health of your vehicle’s most critical system.
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle the programming for you. Simply provide your vehicle’s VIN during or after checkout, and we will flash the module with the latest GM-certified software specific to your vehicle before shipping.
What is a CASE relearn and will I need one?
A CASE (Crankshaft Angle Sensor Error) relearn synchronizes the new PCM with your engine’s crankshaft position sensor. While the vehicle will start and run without it, this procedure is often necessary to turn off the check engine light and ensure optimal performance. It requires a compatible bi-directional scan tool.
Is this a brand new part?
This is a high-quality, genuine GM replacement part that has been meticulously inspected and prepared to provide reliable, long-lasting service for your vehicle.
Where is the PCM located on my 2004 Sierra 2500?
On the 2004 Sierra 2500 and similar GM trucks, the PCM is typically mounted on the driver’s side of the engine compartment, under the battery tray or near the air filter housing.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM controls both engine and transmission functions. If your shifting issues are caused by faulty electronic signals from a failing module, this replacement part is the correct solution.