Restore Peak Performance to Your 2004 GM Truck or SUV
If your 2004 Silverado, Sierra, Tahoe, or other compatible GM vehicle is suffering from perplexing issues like a persistent check engine light, erratic engine behavior, poor fuel mileage, or transmission problems, a failing Powertrain Control Module (PCM) is often the culprit. As the central computer for your vehicle’s engine and transmission, the PCM is critical for smooth, efficient, and reliable operation. This replacement PCM, service number 12586242, is the definitive solution to get your truck back to running like it just rolled off the factory floor.
This isn’t just a generic part. We provide a fully programmed, plug-and-play solution. Upon purchase, you will 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 GM-certified software specific to your vehicle’s exact build. This critical step ensures perfect communication between the module and all other vehicle systems, eliminating the need for an expensive trip to the dealership for programming.
From the Diagnostic Bay
We had a 2004 Sierra 1500 come into the shop with a frustratingly intermittent issue. The owner complained it would randomly stall at stoplights, but then start right back up. There were no consistent trouble codes, just a few random communication loss codes (U-codes) stored in history. We checked all the main power and ground circuits to the PCM and they were solid. On a hunch, we gently tapped on the original PCM with the engine running and were able to make it stall. This confirmed an internal failure in the module. We replaced it with a pre-programmed 12586242 unit, performed the quick security relearn, and the truck ran perfectly. The customer called a week later to say his stalling problem was completely gone.
Is Your 2004 Silverado 1500 PCM Failing?
A faulty engine computer can manifest in numerous ways, often mimicking other component failures. Diagnosing a bad PCM can be tricky, but there are several common indicators that point to the module itself. If your vehicle is exhibiting one or more of the following symptoms, a failing PCM is a likely cause.
Common Symptoms of a Bad ECM/PCM
- ✔ Persistent Check Engine Light (CEL) that won’t clear or returns immediately.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh, erratic, or delayed automatic transmission shifting.
- ✔ Complete no-start condition where the engine cranks but will not fire.
- ✔ Communication errors when trying to connect a diagnostic scan tool.
- ✔ Misfire codes (e.g., P0300) even after replacing plugs, wires, and coils.
- ✔ False sensor readings or codes for components that have tested good.
Simple, Hassle-Free Installation
This module is a direct-fit replacement for the original unit. On most GM trucks and full-size SUVs from this era, the PCM is located in the engine bay, on the driver’s side, often next to or under the battery tray. Installation is straightforward:
- Disconnect the Battery: Always disconnect the negative battery terminal before starting any work on your vehicle’s electrical system.
- Locate and Remove the Old PCM: Unplug the electrical connectors (they have locking tabs) and unbolt the module from its bracket.
- Install the New PCM: Bolt the new module in place and securely reconnect the electrical harnesses.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: In most cases, you will need to perform a simple security relearn procedure, which can be done without any special tools. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the new PCM to synchronize with your vehicle’s anti-theft system.
This module is a direct replacement for service numbers 12586242, 19299226, 89017738 and broadcast codes such as YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, YHTN. It fits a wide range of 2004 GM vehicles including the Silverado, Sierra, Suburban, Tahoe, Yukon, Escalade, Hummer H2, and more. Please verify your part number or consult the detailed fitment list to ensure compatibility.
Frequently Asked Questions
How do I provide my VIN for programming?
After you complete your purchase, you can send us a message with your 17-digit VIN. We cannot ship your part until we receive this information, as the programming is essential for the module to function in your vehicle.
Is this part truly plug-and-play?
Yes, for the most part. Because we program it to your VIN, it will have the correct software for your engine, transmission, and options. However, you will almost always need to perform a security relearn procedure, which takes about 30 minutes and involves cycling the ignition key. Instructions are widely available online for this simple process.
Will this fix my check engine light?
If the check engine light is caused by a faulty PCM, then yes, this will resolve the issue. However, a check engine light can be triggered by hundreds of potential problems. It is always best to have your vehicle scanned for diagnostic trouble codes (DTCs) to help pinpoint the root cause before replacing parts.
My original module has a different service number. Will this work?
This module replaces several service numbers, including 12586242, 19299226, and 89017738. As long as your original part number is on our cross-reference list, this unit will function as a direct replacement once programmed to your VIN.
What tools are needed for installation?
Basic hand tools are all that’s required. Typically, you will need a socket set (10mm is common for the mounting bolts and battery terminal), and possibly a flathead screwdriver to help release the locking tabs on the electrical connectors. No special diagnostic equipment is needed.