Restore Peak Performance to Your GM Truck or SUV
Is your 2004 GMC Sierra, Chevrolet Silverado, or other GM vehicle running poorly? Are you battling persistent check engine lights, rough idling, stalling, or erratic transmission behavior? The Powertrain Control Module (PCM), often called the engine computer or ECM, is the central command center for your vehicle’s engine and transmission. When it fails, it can cause a wide range of frustrating and difficult-to-diagnose problems. This replacement PCM, service number 12586242, is the definitive solution to get your vehicle running reliably again.
This isn’t just a generic part off a shelf. We provide a comprehensive service that makes this a simple, plug-and-play repair. Upon purchase, you simply provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). Our technicians will then flash the module with the latest, most up-to-date factory software directly from General Motors, ensuring it is perfectly matched to your vehicle’s specific configuration. This critical step eliminates the need for an expensive trip to the dealership for programming, saving you both time and money.
From the Diagnostic Bay
We had a 2004 Silverado in the shop that was driving the owner crazy. It had a random, intermittent misfire that wouldn’t set a consistent code. The owner had already replaced spark plugs, wires, and even an ignition coil. After hours of diagnostics, we traced the issue to a failing injector driver circuit inside the original PCM. The computer was intermittently failing to fire the fuel injector on cylinder 3. Installing a correctly programmed PCM like this one solved the problem in under 30 minutes. It’s a reminder that sometimes the issue isn’t with the mechanical parts, but with the computer that controls them.
Common Symptoms of a Failing 2004 Sierra 1500 PCM
- ✔️ Persistent Check Engine Light (CEL) with communication error codes (U-codes) or specific circuit fault codes.
- ✔️ Rough or unstable engine idle.
- ✔️ Unexpected stalling or difficulty starting the engine.
- ✔️ Noticeable decrease in fuel economy.
- ✔️ Harsh or incorrect automatic transmission shifting.
- ✔️ The engine runs in a reduced power or “limp” mode.
- ✔️ Complete no-start condition where the engine cranks but will not fire up.
A True Plug-and-Play Solution
Replacing a modern vehicle’s computer can be intimidating, but our process makes it straightforward. Because we program the module to your VIN before shipping, the complex part is already done. For most vehicles, installation is as simple as disconnecting the battery, swapping the old module with the new one, and performing a simple security relearn procedure that takes about 30 minutes and requires no special tools. This procedure pairs the new computer with your vehicle’s anti-theft system. We provide clear instructions to guide you through this final step.
This module is a direct replacement for service number 12586242 and is also compatible with a wide range of other service numbers, including 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. It fits dozens of 2004 GM models, including the Chevrolet Silverado, Suburban, Tahoe, Avalanche, SSR, Trailblazer; the GMC Sierra, Yukon; the Cadillac Escalade; the Buick Rainier; and more. Please verify your part number or consult the detailed fitment list to ensure compatibility.
Frequently Asked Questions
What is a PCM and what does it do?
The Powertrain Control Module (PCM) is your vehicle’s main computer. It controls all aspects of engine performance, including fuel injection, ignition timing, emissions systems, and automatic transmission shifting, to ensure optimal power, efficiency, and reliability.
Do I need to program this PCM?
No. We handle the programming for you before the item ships. You must provide your vehicle’s VIN at checkout so we can load the correct, updated GM software for your specific vehicle. This makes the unit ready for installation when it arrives.
Where is the PCM located on my 2004 Sierra 1500?
On most 2004 GM trucks and full-size SUVs like the Sierra, Silverado, and Tahoe, the PCM is located in the engine bay on the driver’s side, under the battery tray or near the firewall.
What is the security relearn procedure?
The security relearn, or anti-theft relearn, is a simple procedure that syncs the new PCM to your vehicle’s existing keys and security system. It typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating the cycle three times. We include detailed instructions for this process.
Will this fix my check engine light?
If the check engine light is caused by a faulty PCM, then yes, this part will resolve the issue. However, it’s crucial to properly diagnose the codes before ordering. This PCM will not fix problems related to other faulty sensors or mechanical components.
How do I find the correct part number for my vehicle?
The service number is printed on a white sticker on your original computer. This module, 12586242, replaces many different service numbers. As long as your vehicle is listed in our compatibility chart, this programmed module will work for you.