Is Your 2004 Avalanche Running Rough?
A failing Powertrain Control Module (PCM), the central computer of your truck, can lead to a host of frustrating and difficult-to-diagnose issues. From a persistent check engine light to poor performance and even a no-start condition, a faulty PCM can bring your vehicle to a standstill. This replacement PCM, service number 12586242, is the definitive solution to restore your truck’s reliability and performance. We take the guesswork out of the repair by pre-programming the module to your vehicle’s specific Vehicle Identification Number (VIN) before it ships, ensuring a seamless installation process.
From the Diagnostic Bay
We once had a 2004 Sierra with the 6.0L come in with an intermittent misfire on cylinder 3 that no one could solve. The owner had replaced the spark plug, wire, coil pack, and even the fuel injector. The misfire would disappear for a day and then return. After hooking up our diagnostic tools, we noticed the control signal for the cylinder 3 injector was erratic. The problem wasn’t any of the new parts; it was a failing driver circuit inside the original PCM. Installing a correctly programmed replacement like this one solved the problem instantly, saving the customer from throwing more parts at a computer-level issue.
Common Symptoms of a Failing PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes, especially communication or internal processor fault codes.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Intermittent or complete no-start condition where the engine cranks but won’t fire.
- ✔ Communication issues with diagnostic scan tools.
- ✔ Failure to pass emissions testing due to readiness monitor issues.
The Perfect Solution for Your 2004 Avalanche PCM
Don’t settle for a generic, unprogrammed module that will require an expensive trip to the dealership. This PCM is a direct-fit replacement for your 2004 Avalanche PCM and a wide range of other GM trucks and SUVs from that model year. The key benefit is our professional programming service. When you place your order, simply provide us with your VIN. Our technicians will flash the module with the latest, most stable software updates directly from GM. This not only ensures compatibility but can also resolve underlying software bugs that may have existed in your original factory programming.
Simple Installation Process
Replacing the PCM is a straightforward job for a DIY mechanic. On most compatible trucks and SUVs like the Avalanche, Sierra, and Silverado, the PCM is located on the driver’s side, under the battery tray.
- Disconnect the Battery: Always start by disconnecting the negative battery terminal.
- Access the PCM: You may need to remove the battery and its tray to access the module.
- Swap Connectors: Carefully unplug the electrical connectors from the old PCM and connect them to your new, pre-programmed module. The connectors are color-coded and keyed to prevent mistakes.
- Reassemble: Secure the new PCM and reinstall the battery tray and battery.
- Perform Security Relearn: You will need to perform a simple key-cycle procedure to sync the new PCM with your vehicle’s anti-theft system. This typically takes about 30 minutes and does not require special tools.
Guaranteed Compatibility
This module is a direct replacement for units with service number 12586242 and is also interchangeable with the following service numbers: 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. It fits a wide variety of 2004 GM models, including the Chevrolet Silverado, Suburban, Tahoe; GMC Sierra, Yukon; Cadillac Escalade; and more. Please verify your original part number to ensure a perfect match.
Frequently Asked Questions
Do I need to have this computer programmed?
No. We handle all the programming for you before shipment. Simply provide your vehicle’s VIN after you place your order, and it will arrive ready to be installed.
What is a VIN and where do I find it?
The VIN is your vehicle’s unique 17-digit identification number. You can find it on your driver’s side dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
What is the security relearn procedure?
This is a required step to sync the new PCM with your truck’s anti-theft system. It’s a simple process that involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating this cycle three times. We include easy-to-follow instructions with your order.
Will this fix my specific problem?
If your vehicle’s issues have been correctly diagnosed as a faulty PCM, this part will be the solution. It is designed to correct problems directly related to the computer’s function, such as internal circuit failures, software corruption, and communication errors.
Is any other work required after installation?
In some cases, a Crankshaft Variation Relearn (also known as a CASE Relearn) may be needed to clear certain engine codes related to misfires. This procedure typically requires a bi-directional scan tool, which most professional repair shops have.