Is Your 2004 GM Truck or SUV Running Rough? The PCM Might Be the Culprit.
If your 2004 Chevrolet SSR, GMC Sierra, Cadillac Escalade, or other compatible GM vehicle is experiencing frustrating issues like stalling, poor fuel economy, a persistent check engine light, or a complete no-start condition, a failing Powertrain Control Module (PCM) is often the root cause. As the central computer for your engine and transmission, its proper function is critical for performance, efficiency, and reliability. This replacement PCM, part number 12586242, is the definitive solution to restore your vehicle’s factory performance and get you back on the road with confidence.
From the Diagnostic Bay
We had a 2004 Sierra 1500 towed in that was randomly stalling and throwing a slew of communication error codes. The owner had already replaced the alternator and battery, thinking it was a voltage issue. After hours of chasing wires, we checked the PCM connectors and found no issues. On a hunch, we swapped in a known-good test module, and the truck fired up and ran perfectly. The original PCM had an internal intermittent failure that would only show up when warm. It’s a classic example of how a faulty module can mimic other problems, making accurate diagnosis tricky. A direct-fit, correctly programmed replacement like this one is the only way to ensure a lasting repair.
Common Symptoms of a Failing 2004 SSR PCM
A failing engine computer can manifest in numerous ways. If you’re noticing any of the following, it’s time to consider a replacement:
- ✔ Check Engine Light is on with various trouble codes (DTCs).
- ✔ Engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling, especially when warm.
- ✔ Noticeable decrease in fuel mileage.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass state emissions testing.
- ✔ Communication errors with diagnostic scan tools.
A True Plug-and-Play Solution
Don’t waste time and money at a dealership. We take the hassle out of PCM replacement. When you order from us, you’re not just getting a part; you’re getting a complete service. We use your vehicle’s Vehicle Identification Number (VIN) to flash the module with the latest, most stable software updates directly from GM. This ensures that your new computer is perfectly matched to your vehicle’s specific configuration, including engine, transmission, and emissions equipment. The result is a simple, plug-and-play installation process that requires no additional programming on your end.
This module is a direct replacement for service numbers 12586242, 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. It fits a wide range of 2004 GM vehicles, including the Chevrolet SSR, Silverado, Suburban, Tahoe, Avalanche; the GMC Sierra, Yukon; the Cadillac Escalade; the Hummer H2; and more. Please verify your part number or consult the detailed fitment list to ensure compatibility.
Frequently Asked Questions
Do I need to have this PCM programmed by a dealer?
No. This PCM comes fully programmed to your vehicle’s specific VIN before it is shipped. It is ready for installation right out of the box, saving you the cost and inconvenience of a dealership visit.
Where is the PCM located on my 2004 GM truck or SUV?
On most compatible trucks and full-size SUVs (like the Sierra, Silverado, Tahoe, Yukon, Escalade), the PCM is located in the engine bay on the driver’s side, under the battery tray. On models like the SSR, Trailblazer, and Envoy, it is typically found next to the air filter box.
What is a CASE Relearn and will I need to perform one?
A CASE (Crankshaft Angle Sensor Error) relearn procedure synchronizes the new PCM with your engine’s crankshaft position sensor. While many vehicles will start and run without it, performing this simple procedure with a capable scan tool is recommended to prevent a P1336 trouble code and ensure optimal engine timing and misfire detection. Most local repair shops can perform this for you.
How do I provide my VIN for programming?
After you complete your purchase, you will need to send us your 17-digit VIN. You can typically add this as a note during checkout or reply to your order confirmation email. We cannot ship your part until we receive your VIN.
Will this fix my vehicle’s shifting problems?
In many cases, yes. The PCM also controls transmission functions, including shift points and line pressure. If your transmission issues are caused by faulty electronic commands from the PCM, this replacement module will resolve them. However, it will not fix internal mechanical failures within the transmission itself.