Restore Your Truck’s Power and Reliability
Is your 2004 Chevrolet Avalanche 1500 running rough, stalling, or showing a persistent check engine light? These are common indicators of a failing Powertrain Control Module (PCM), the central computer responsible for managing your engine’s performance, fuel economy, and emissions. A faulty PCM can disrupt everything from ignition timing to transmission shifting, leaving you with an unreliable and inefficient vehicle. This replacement PCM, part number 12586242, is the definitive solution to restore your truck’s factory performance and get you back on the road with confidence.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We take the hassle and expense out of the repair process by programming the module specifically for your vehicle using your VIN. This ensures that the computer has the latest software updates from GM and is perfectly matched to your truck’s specific options and configuration. Simply provide your VIN after purchase, and we’ll handle the complex programming before it even ships.
From the Diagnostic Bay
We had a 2004 Sierra 1500 (which uses this exact same PCM) come into the shop with a frustrating, intermittent no-start condition. The owner had already replaced the battery, alternator, and starter to no avail. The truck would crank but wouldn’t fire, and there were no consistent trouble codes. After checking fuel pressure and spark, which were also intermittent, we hooked up our diagnostic scanner and monitored the PCM data stream. We noticed the PCM was randomly losing communication and failing to command the fuel pump relay. After verifying all power and ground circuits to the module were solid, we knew we had a failing computer. We installed a VIN-programmed 2004 Avalanche 1500 PCM like this one, performed the security relearn, and the truck fired up instantly. It’s a classic case where the central ‘brain’ was causing ghost-like symptoms that were hard to pin down without looking at the core electronics.
Is Your 2004 Avalanche 1500 PCM Failing?
A failing engine computer can manifest in numerous ways, often mimicking other component failures. If you’re experiencing any of the following, it’s a strong sign that your PCM needs attention. This module is the correct fix for these common issues.
- ✔ Check Engine Light: An illuminated check engine light, especially with communication error codes (U-codes) or internal processor fault codes (P0600-P0606), is a primary symptom.
- ✔ Engine Stalling or Misfiring: The engine may stall unexpectedly while driving or at idle, and you might experience random misfires that aren’t tied to a specific spark plug or coil.
- ✔ No-Start Condition: Your truck cranks but refuses to start, often due to the PCM not commanding the fuel pump or ignition system.
- ✔ Poor Fuel Economy: A sudden and unexplained drop in MPG can be caused by the PCM failing to properly calculate the air-fuel mixture.
- ✔ Erratic Transmission Shifting: The PCM also controls transmission functions, so you might notice harsh shifts, delayed engagement, or getting stuck in a gear.
- ✔ Failed Emissions Test: An inability to pass a smog check is often directly related to a malfunctioning engine control module.
Plug-and-Play Solution
This module is a direct replacement for service number 12586242 and a wide range of other compatible service numbers including YFKD, YFKF, YFKH, YFKJ, YFXN, and more. It fits a variety of 2004 GM trucks and SUVs like the Sierra, Silverado, Yukon, Tahoe, Escalade, and Suburban. By programming it to your vehicle’s VIN, we ensure it communicates seamlessly with your truck’s existing systems. While the programming is done for you, please note that a security relearn procedure (also known as a CASE relearn) may be necessary after installation. This procedure syncs the new PCM with your vehicle’s anti-theft system and crankshaft position sensor, and can typically be performed by a qualified mechanic with a professional-grade scan tool.
Frequently Asked Questions
Do I need to program this PCM?
No. We handle all the programming for you before shipping. Simply provide us with your vehicle’s VIN during or after checkout, and we will flash the module with the latest GM-certified software for your exact vehicle.
Where is the PCM located on my 2004 Avalanche 1500?
On most 2004 GM trucks like the Avalanche, Sierra, and Silverado, the PCM is located in the engine bay on the driver’s side, under the battery tray or near the airbox.
What is a CASE relearn and is it required?
A Crankshaft Variation Relearn (CASE relearn) is a procedure that syncs the new PCM with your crankshaft position sensor. This is often required to prevent a P0315 trouble code and ensure accurate misfire detection. Most automotive shops with a capable bi-directional scan tool can perform this procedure in a few minutes.
Will this fit other GM vehicles?
Yes, this PCM with service number 12586242 is compatible with a wide array of 2004 GM models, including the Sierra 1500/2500/3500, Silverado 1500/2500/3500, Tahoe, Suburban, Yukon, Escalade, Hummer H2, and more. Please verify your original part number to ensure compatibility.
Is this a simple DIY installation?
The physical installation is straightforward for someone with basic mechanical skills. It involves disconnecting the battery, removing the old module, and installing the new one. However, the post-installation security/CASE relearn procedure typically requires a professional scan tool, so we recommend professional installation.