Is your 2004 GM truck or SUV suffering from frustrating engine problems? A faulty Powertrain Control Module (PCM) is often the culprit behind issues like stalling, erratic performance, poor fuel economy, and a persistent check engine light. This direct-fit replacement PCM, part number 12586242, is the definitive solution to restore your vehicle’s reliability and performance. It serves as the central computer for your engine, managing everything from fuel injection and ignition timing to transmission shifting and emissions control. When it fails, the entire vehicle can become unreliable or even undrivable.
We take the guesswork out of the repair process. Unlike sourcing a used module from a junkyard that may have its own issues or incorrect software, this unit is meticulously prepared for your specific vehicle. Upon purchase, simply provide us with your vehicle’s VIN. Our technicians will then program the module with the latest GM-certified software updates. This ensures not only perfect compatibility but also resolves many of the original drivability issues that were fixed in later software releases from the factory. This is a crucial step that dealerships charge a premium for, but we include it with your purchase.
From the Diagnostic Bay
We had a 2004 GMC Sierra 1500 in the shop with a classic case of intermittent no-start. The owner had already replaced the battery, alternator, and starter to no avail. The truck would run fine for days, then suddenly refuse to crank. After hours of chasing wires, we noticed the problem only happened on hot days after the truck had been sitting in the sun. We put a heat gun on the PCM, and sure enough, the truck wouldn’t start. A quick cool-down with compressed air, and it fired right up. The internal circuits of the original PCM were failing under thermal stress—a common issue. We installed a VIN-programmed module just like this one, performed the security relearn, and the truck has been starting reliably ever since. Don’t let a failing computer leave you stranded.
Diagnosing a Failing 2004 SSR PCM
A failing engine computer can manifest in numerous ways, often mimicking other component failures. If you’re experiencing a combination of the symptoms below, it’s highly likely your PCM is the root cause. Replacing it with this pre-programmed unit is the most effective way to get your vehicle running properly again. This module is a direct replacement for service numbers 12586242, 19299226, 89017738, and many others, ensuring wide compatibility across the 2004 GM lineup.
Common Symptoms of a Bad ECM
- ✔ Check Engine Light: The module may set various trouble codes, including communication errors (U-codes) or internal processor fault codes (P06xx series).
- ✔ No-Start or Hard Starting: The engine may crank but fail to start, or take an excessively long time to fire up, either hot or cold.
- ✔ Stalling and Misfires: The engine may stall unexpectedly while driving or at idle. You may also notice random misfires or a rough idle.
- ✔ Poor Performance and Fuel Economy: A failing PCM can’t properly manage the engine, leading to a noticeable drop in power, acceleration, and miles per gallon.
- ✔ Failed Emissions Test: Incorrect air/fuel mixture or sensor readings managed by a faulty PCM will almost certainly cause a vehicle to fail a smog check.
- ✔ Erratic Transmission Shifting: The PCM works with the transmission controller, and a fault can lead to harsh shifts, delayed engagement, or being stuck in one gear.
This unit is a simple plug-and-play installation. Once you receive the programmed module, you’ll need to perform a security relearn procedure (often called a CASE relearn or anti-theft relearn), which can typically be done without special tools and takes about 30 minutes. Instructions are readily available online for your specific model. By providing your VIN, we ensure this 2004 SSR PCM arrives ready to integrate seamlessly with your vehicle’s systems, making it the most reliable and straightforward repair for your GM truck or SUV.
Frequently Asked Questions
Do I need to send my old computer (core) back?
No, there is no core charge or requirement to return your old module. You can keep it or dispose of it at your convenience.
What information do you need from me?
After you place your order, we will need your vehicle’s 17-digit Vehicle Identification Number (VIN). This is essential for us to load the correct GM-certified software and calibrations for your specific engine, transmission, and options.
Is this a difficult part to install?
Installation is straightforward for most DIY mechanics. The PCM is typically located in the engine bay (next to the air box or under the battery). It involves disconnecting the battery, unplugging the electrical connectors, and unbolting the module. After installing the new one, you will need to perform a security relearn procedure, which pairs the new computer to your vehicle’s anti-theft system.
Will this fix my specific problem?
This PCM will correct any issues directly caused by a faulty engine computer. While we cannot diagnose your vehicle remotely, the symptoms listed on this page are the most common indicators of PCM failure. This part is guaranteed to be a functional, correctly programmed module.
What vehicles does this module fit?
This PCM fits a wide range of 2004 GM trucks and SUVs, including the Chevrolet SSR, Silverado, Suburban, Tahoe, Avalanche, Trailblazer EXT; GMC Sierra, Yukon, Envoy XL/XUV; Cadillac Escalade; Hummer H2; Buick Rainier; and Isuzu Ascender. Please verify your original part number or service ID matches the list provided to ensure compatibility.