Is your 2004 Chevrolet Avalanche 1500 running rough, stalling, or displaying a persistent check engine light? These are classic signs of a failing Powertrain Control Module (PCM), the central computer of your vehicle. A faulty PCM can disrupt everything from fuel economy and transmission shifting to engine performance and emissions. This replacement PCM, service number 12586242, is the definitive solution to restore your truck’s original performance and reliability.
This isn’t just a part in a box; it’s a complete, ready-to-install solution. Upon purchase, simply provide us with your vehicle’s VIN. Our technicians will then program the module with the latest GM factory software specific to your Avalanche. This critical step ensures seamless communication with all your vehicle’s systems, eliminating the need for an expensive trip to the dealership for programming. It arrives at your door ready for installation.
From the Diagnostic Bay
We had a 2004 Sierra 1500 (which uses this exact same PCM) come into the shop with a bizarre issue. The owner complained of random stalling at stoplights and a transmission that wouldn’t shift out of second gear intermittently. He had already replaced the throttle body and a transmission solenoid with no luck. After hooking up our diagnostic scanner, we saw no communication from the PCM. A quick check of the power and ground circuits to the module confirmed they were good. The internal processor of the original PCM had simply failed. We installed one of our pre-programmed units, performed the quick security relearn, and the truck was back on the road in under an hour, running perfectly. It’s a reminder that sometimes the most complex symptoms point back to the vehicle’s brain.
Common Symptoms of a Failing GM PCM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes
- ✔ Engine stalling, stumbling, or misfiring
- ✔ Harsh or erratic automatic transmission shifting
- ✔ A complete no-start condition where the engine cranks but won’t fire
- ✔ Noticeable decrease in fuel economy
- ✔ Failure to pass state emissions testing
- ✔ Communication errors with diagnostic scan tools
Direct Replacement 2004 Avalanche 1500 PCM
This module is a direct-fit replacement for a wide range of 2004 GM trucks and SUVs. It is compatible with multiple service numbers, including 12586242, 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, and YHTN. By matching your original part number or service ID to this list, you can be confident in its compatibility. The physical installation is straightforward, typically located under the hood on the driver’s side, near the battery. Once installed, you may need to perform a simple security relearn procedure (also known as a CASE relearn) to sync the new computer with your vehicle’s anti-theft system and crankshaft position sensor, a process that can often be done without special tools.
Don’t let a faulty engine computer keep your reliable GM truck off the road. This pre-programmed 2004 Avalanche 1500 PCM is your key to solving complex electronic issues, restoring lost power, and ensuring your vehicle operates as the factory intended. Get back the smooth performance and peace of mind you expect from your truck.
Do I need to program this computer?
No. This Powertrain Control Module comes pre-programmed to your vehicle’s specific VIN. You must provide your VIN at checkout or after your purchase so we can load the correct GM software before shipping.
Where is the PCM located on my 2004 Avalanche 1500?
On the 2004 Avalanche 1500, as well as most similar GM trucks like the Sierra and Silverado, the PCM is located in the engine bay on the driver’s side, under the battery tray or next to the fender.
Will this fix my check engine light?
If the check engine light is caused by a fault within the PCM itself, then yes, this part will resolve the issue. However, it is crucial to properly diagnose the trouble codes first, as the light could be triggered by a faulty sensor or other component that the PCM is correctly identifying.
What is a security or CASE relearn procedure?
After installation, your vehicle’s anti-theft system may prevent it from starting. A security relearn syncs the new PCM to your keys. A Crankshaft Variation (CASE) relearn syncs the PCM to the crankshaft position sensor to prevent misfire codes. The security relearn can often be done without tools, while a CASE relearn typically requires a capable scan tool.
Is this compatible with other GM vehicles?
Yes, this PCM fits a wide variety of 2004 GM models including the Sierra, Silverado, Tahoe, Yukon, Suburban, Escalade, Envoy, Rainier, and SSR with compatible engines. Please verify your original service number against the list provided to ensure proper fitment.