Restore Peak Performance to Your GM Vehicle with a VIN-Programmed Engine Computer
If you’re dealing with frustrating engine problems in your 2004 Avalanche 2500—like a persistent check engine light, poor fuel mileage, or a no-start condition—a failing Powertrain Control Module (PCM) is often the culprit. As the central computer for your engine, its proper function is critical. This replacement PCM, part number 89017739, is the reliable, straightforward solution to get your truck or van running like new again. We take the guesswork out of the repair by flashing the module with the latest GM software updates, specifically matched to your vehicle’s VIN before it ships. This means no expensive trips to the dealership for programming are required.
From the Diagnostic Bay: The Misleading Misfire
I once had a 2004 Sierra 2500 with the 8.1L in my shop that was driving the owner crazy. It had a random, intermittent misfire that wouldn’t set a specific cylinder code, just a P0300 (Random/Multiple Misfire Detected). The owner had already replaced plugs, wires, and even a coil pack with no success. After hooking up my scan tool and watching the live data, I noticed the fuel trim and injector pulse width were erratic. This pointed away from a mechanical issue and toward the controller. We swapped in a pre-programmed 2004 Avalanche 2500 PCM (the same unit used in his Sierra), performed a quick security relearn, and the truck ran perfectly. The original PCM’s internal processor was failing under load, causing faulty calculations. It’s a classic case where the problem isn’t the engine hardware, but the brain controlling it.
Common Signs of a Failing GM PCM
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or other communication faults.
- ✔ Your vehicle fails to start or starts and then immediately stalls.
- ✔ Noticeable decrease in fuel economy.
- ✔ Engine performance issues such as rough idling, stumbling, or hesitation.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass state emissions testing.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- ✔ Locate the PCM: On the 2004 Avalanche 2500, the PCM is located on the driver’s side, in the front, underneath the battery tray. You will need to remove the battery to access it.
- ✔ Disconnect Connectors: Carefully unplug the electrical harness connectors from the old module. There are typically release tabs that need to be pressed or lifted. Avoid pulling on the wires themselves.
- ✔ Remove the Old Module: Unbolt the PCM from its mounting bracket.
- ✔ Install the New Module: Mount your new, pre-programmed PCM and securely reconnect the electrical connectors. You should hear a ‘click’ as they lock into place.
- ✔ Reconnect Battery: Reinstall and reconnect the battery.
- ✔ Perform Security Relearn: You will need to perform a simple key-on/key-off security relearn procedure to sync the new PCM with your vehicle’s anti-theft system. This typically takes about 10-15 minutes and does not require special tools. Instructions are readily available online for your specific model.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 89017739 and 12586243. It fits a wide range of 2004 GM vehicles. Please confirm your vehicle is on the list below. Note that specific engine or option codes may apply.
- Chevrolet Avalanche 2500 (2004) – (LH front under battery)
- Chevrolet & GMC Express/Savana Vans (1500, 2500, 3500) (2004) – (LH rear engine compartment)
- Chevrolet & GMC S10/S15/Sonoma (2004) – (RH front engine compartment)
- Chevrolet & GMC Silverado/Sierra Pickups (1500, 2500, 3500) (2004) – (Gasoline, LH front under battery)
- Chevrolet Astro & GMC Safari (2004) – (LH front by battery)
- Chevrolet Blazer S10 & GMC Jimmy S15 (2004) – (RH front engine compartment)
- Chevrolet Corvette (2004) – (RH engine compartment, ID 12586243)
- Chevrolet SSR (2004) – (Next to air box)
- Chevrolet Suburban 2500 (2004) – (8.1L, LH front under battery)
- Chevrolet Trailblazer EXT (2004) – (5.3L, next to air box)
- Buick Rainier (2004) – (5.3L, next to air box)
- Cadillac CTS (2004-2005) – (V-Series, RH engine compartment, ID 12586243)
- GMC Envoy XL / XUV (2004) – (5.3L, next to air box)
- Pontiac GTO (2004) – (Main, LH engine)
- GMC Yukon XL 2500 (2004) – (8.1L, LH front under battery)
Frequently Asked Questions
Frequently Asked Questions
Do I need to send my old PCM back (core charge)?
No core charge is required for this purchase. You can keep or recycle your old module.
How do I provide my VIN for programming?
After you complete your purchase, simply send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot ship your order until we receive it.
Is this a simple plug-and-play installation?
Almost. Because we program it to your VIN, it’s ready to go. However, you will need to perform a standard GM security relearn procedure, which involves a series of key cycles. This syncs the module to your vehicle’s anti-theft system and can be done in your driveway without any special tools.
Will this fix my specific problem?
This PCM corrects issues directly caused by a faulty module. While it resolves the most common electronic engine problems, we always recommend a proper diagnosis to confirm the PCM is the point of failure before ordering.
What if my original part number is 12586243?
This module, 89017739, is fully compatible and interchangeable with part number 12586243. It will function identically in your vehicle.