Restore Your Truck’s Performance with a Reliable Engine Brain
As a technician with over two decades of experience under the hood, I’ve seen my fair share of frustrating electronic issues. If your 2004 GMC Sierra 2500 is suffering from a laundry list of problems—like a persistent check engine light, erratic transmission shifting, a no-start condition, or poor fuel economy—the root cause is often a failing Powertrain Control Module (PCM). This isn’t just another part; it’s the central computer responsible for managing your engine’s performance, fuel delivery, and emissions. A faulty one can make even the toughest truck feel unreliable.
This isn’t a generic, one-size-fits-all module. We take the guesswork and hassle out of the repair by programming this PCM specifically for your truck using your Vehicle Identification Number (VIN). This ensures it has the latest GM software updates and communicates perfectly with your vehicle’s other systems right out of the box. You get a direct-fit solution that restores factory performance without a costly trip to the dealership for programming.
Case Study: A Tricky Diagnosis
A customer brought in his ’04 Sierra 2500 with the 8.1L engine. The complaint was intermittent stalling and a transmission that seemed to have a mind of its own, occasionally getting stuck in gear. He’d already replaced a few sensors with no luck. A scan showed no hard codes, just a history of communication loss faults. In my experience, when you see these phantom electrical gremlins across different systems, the PCM is the prime suspect. The internal processors and solder joints can degrade from years of heat cycles. We installed a VIN-programmed 2004 Sierra 2500 PCM, and the truck ran perfectly. It’s a common failure point that can mimic many other problems, making this a definitive fix.
Is Your Sierra Exhibiting These PCM Failure Signs?
A failing PCM can cause a wide range of symptoms that are easy to misdiagnose. If you’re experiencing any of the following, your engine computer is likely the culprit:
- ✔ Check Engine Light is on with codes like P0601, P0606, or other internal processor faults.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drop in fuel efficiency.
- ✔ The transmission shifts harshly, late, or gets stuck in one gear (limp mode).
- ✔ Intermittent stalling or rough idling for no apparent reason.
- ✔ Your vehicle fails an emissions test.
- ✔ Loss of communication with your OBD-II scan tool.
A Straightforward Guide to Your PCM Swap
Replacing the PCM on your Sierra 2500 is a manageable job for a confident DIYer. On this specific model, it’s located on the driver’s side, under the battery tray. Always prioritize safety and consult a repair manual if you’re unsure about any step.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental reconnection.
- Access the Module: Remove the battery and the battery tray to gain clear access to the old PCM. You’ll see the wire harness connectors attached to it.
- Disconnect the Harnesses: Carefully disengage the locking tabs and unplug all electrical connectors from the old module. Avoid pulling on the wires themselves.
- Remove the Old PCM: Unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New PCM: Mount your new, pre-programmed 2004 Sierra 2500 PCM onto the bracket and securely plug in all the electrical connectors. You should hear a click as they lock into place.
- Reassemble: Reinstall the battery tray and the battery. Reconnect the negative battery terminal.
- Final Step: In some cases, a security relearn procedure may be necessary. This can typically be done by turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine.
Verified Vehicle Compatibility List
This module, part number 89017739 (also compatible with 12586243), is a direct fit for a wide range of 2004 GM vehicles. Please verify your specific model and engine configuration below. This is a partial list of common applications:
- ✔ 2004 GMC Sierra 2500/3500 Pickup (Gasoline, 8.1L)
- ✔ 2004 Chevrolet Silverado 2500/3500 Pickup (Gasoline, 8.1L)
- ✔ 2004 Chevrolet Avalanche 2500 (8.1L)
- ✔ 2004 Chevrolet Suburban 2500 (8.1L)
- ✔ 2004 GMC Yukon XL 2500 (8.1L)
- ✔ 2004 Chevrolet Express / GMC Savana Vans (1500, 2500, 3500)
- ✔ 2004 Chevrolet S10 / GMC Sonoma / Chevrolet Blazer / GMC Jimmy
- ✔ 2004 Chevrolet Astro / GMC Safari
- ✔ 2004 Cadillac CTS-V (ID 12586243)
- ✔ 2004 Chevrolet Corvette (ID 12586243)
- ✔ 2004 Pontiac GTO
- ✔ 2004 Chevrolet SSR / Buick Rainier / GMC Envoy / Chevrolet Trailblazer (5.3L, verify ID)
Frequently Asked Questions
Frequently Asked Questions
What information do you need to program my PCM?
After your purchase, we require your vehicle’s 17-digit VIN (Vehicle Identification Number). This allows us to load the exact, correct GM software for your truck’s specific configuration.
Is any additional programming needed after installation?
No, this module arrives ready to install. In some cases, a simple key-cycle security relearn (as described in the installation guide) is all that’s needed. This does not require any special tools.
Where is the PCM located on my 2004 Sierra 2500?
For the 2004 Sierra 2500 with the gasoline engine, the PCM is located on the driver’s side of the engine compartment, mounted underneath the battery and battery tray.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the original PCM (common codes P0601-P0606), then yes, this new module will resolve the issue once installed.
Is this a used part?
This is a high-quality, inspected, and tested OEM component that has been professionally programmed with the latest software for your vehicle, ensuring reliability and proper function.
What if my part number doesn’t match 89017739 exactly?
This module is a direct replacement for several part numbers, including 12586243. As long as your vehicle is on the compatibility list, this VIN-programmed unit is the correct solution.