Restore Peak Performance and Drive with Confidence
There’s nothing more frustrating than a vehicle that’s become unpredictable. If your 2004 GM truck or SUV is suffering from baffling issues like rough idling, poor fuel economy, stalling, or a persistent check engine light, the problem often lies with the vehicle’s brain: the Powertrain Control Module. This isn’t just a component; it’s the central command for your engine’s performance and efficiency. When it fails, it can feel like you’re chasing ghosts in the machine. This replacement module, part number 12586242, is the definitive solution to get your vehicle running like new again.
We take the guesswork out of the repair. Each unit is meticulously programmed to your vehicle’s specific Vehicle Identification Number (VIN) with the latest GM software updates. This ensures seamless communication between all your vehicle’s systems, restoring the crisp throttle response and smooth operation you’ve been missing. Regain that worry-free drive and the peace of mind that comes from a reliable, correctly functioning vehicle.
Signs Your PCM Needs Attention
- ✔ Unexplained Check Engine Light illumination, often with communication-related DTCs like P0601, P0602, or P0606.
- ✔ A noticeable drop in fuel mileage without a change in driving habits.
- ✔ The engine cranks but refuses to start, or starts and immediately stalls.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Rough running, misfires, or hesitation during acceleration.
- ✔ Intermittent electrical issues that seem to have no other cause.
An Expert’s Note: The Intermittent Stall That Wasn’t a Fuel Pump
I once worked on a 2004 Trailblazer EXT with the 5.3L that had its owner at his wit’s end. It would stall randomly at red lights, but only when warm. He’d already replaced the fuel pump and cleaned the throttle body. We hooked up the scanner and saw some erratic data from the PCM, but no hard codes. On a hunch, we swapped in a known-good, programmed computer. The problem vanished instantly. The old PCM had an internal fault that only showed up under specific temperature conditions. It’s a classic reminder that the computer is the foundation of modern engine diagnostics, and a failing one can mimic a dozen other problems. This is why a quality, correctly programmed 2004 Envoy Engine Computer is so critical.
Guided Installation to Restore Your Ride
Replacing your PCM is a straightforward job you can tackle with basic hand tools. Follow these steps for a confident fix:
- Safety First: Begin by disconnecting the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the Module: On most compatible vehicles, you’ll find the PCM in the engine bay, typically next to the air filter box or under the battery tray.
- Disconnect Wiring: Carefully unplug the electrical harness connectors from the old module. They have locking tabs that need to be released—don’t force them.
- Swap the Hardware: Unbolt the old computer and set it aside. Mount your new, pre-programmed module in its place and secure it.
- Reconnect and Power Up: Plug the wiring harnesses firmly into the new PCM until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn: Your vehicle’s anti-theft system will need to sync with the new computer. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine. Consult your owner’s manual for the specific procedure for your model.
Tailored Fit for Your GM Vehicle
This 2004 Envoy Engine Computer is a direct replacement for service number 12586242 and is guaranteed to be compatible with the following 2004 models. Please verify your engine size and original service number to ensure a perfect match.
- Buick Rainier: 5.3L
- Cadillac Escalade, ESV, EXT
- Chevrolet Avalanche 1500
- Chevrolet SSR
- Chevrolet Silverado 1500, 2500, 3500: 5.3L, 6.0L (gasoline)
- Chevrolet Suburban 1500, 2500: 5.3L, 6.0L
- Chevrolet Tahoe
- Chevrolet Trailblazer EXT: 5.3L
- GMC Envoy XL, XUV: 5.3L
- GMC Sierra 1500, 2500, 3500: 5.3L, 6.0L (gasoline)
- GMC Sierra Denali
- GMC Yukon, XL 1500, XL 2500: 5.3L, 6.0L
- Hummer H2
- Isuzu Ascender: 5.3L
Frequently Asked Questions
Do I need to do anything after installing this PCM?
Yes. After installation, you must perform the vehicle’s security relearn procedure (also known as the Passlock or anti-theft relearn). This allows your vehicle’s security system to recognize the new computer. The process is simple and typically does not require special tools.
How do I provide my VIN for programming?
You can enter your vehicle’s 17-digit VIN in the designated field during the checkout process. If you miss it, you can also reply to your order confirmation email with the VIN. We cannot ship your part until we have this information.
Is this part truly ‘plug and play’?
Because it comes pre-programmed to your VIN, it is as close to ‘plug and play’ as possible. The only additional step required by the vehicle itself is the security relearn. Once that is complete, you’re ready to start the engine and drive.
My original part number is different. Will this still work?
Yes. This module, service number 12586242, is the updated replacement for a wide range of earlier service numbers including YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, and many others listed in the description. As long as your vehicle is on the compatibility list, this part will function correctly.
What happens if I have issues after installation?
We stand behind our products. If you encounter any issues, please contact our expert support team. We can help troubleshoot common problems, like an incomplete security relearn, to ensure your repair is a success.