Restore Peak Performance and Drive with Confidence
Is your trusty 2004 GM truck or SUV suddenly feeling tired, unpredictable, or just not itself? Stalling at intersections, shifting erratically, or displaying a stubborn Check Engine Light can turn a reliable workhorse into a source of daily frustration. You’re not just losing performance; you’re losing the peace of mind that comes with a dependable vehicle. This is where the heart of your vehicle’s operations—the Engine Control Module—often plays a critical role. We offer a direct, reliable solution: a replacement PCM, part number 12586242, professionally programmed to your vehicle’s specific VIN with the latest GM software updates.
An Expert’s Note on Diagnosis
Before replacing any module, always check the basics first. A weak battery or poor ground connections (especially the main ground strap from the engine to the frame) can mimic PCM failure. A quick check with a multimeter can save you time and confirm you’re targeting the right component. A solid 12.6V at rest and over 13.5V while running is what you want to see.
Signs Your Engine Computer Needs Attention
A failing PCM can cause a cascade of confusing issues. If you’re experiencing any of the following, this module is the likely solution to get you back on the road smoothly.
- ✔ Unexplained Stalling: The engine quits unexpectedly, often at low speeds or when coming to a stop.
- ✔ Harsh or Failed Shifting: Your transmission may slam into gear, hesitate, or fail to shift correctly.
- ✔ No-Start Condition: The engine cranks but refuses to start, even with a good battery and starter.
- ✔ Persistent Check Engine Light: You may see codes related to internal module failure, communication errors (U-codes), or multiple unrelated sensor faults.
- ✔ Poor Fuel Economy: The engine runs rich or lean, drastically reducing your MPG.
- ✔ Reduced Engine Power: The vehicle feels sluggish and lacks the acceleration it once had.
Your Guided Path to a Successful Installation
Replacing your 2004 GM Engine Computer is a straightforward job you can tackle with basic tools. Follow these steps for a confident repair that restores your vehicle’s reliability.
- Safety First: Begin by disconnecting the negative terminal of your vehicle’s battery to prevent any electrical shorts. This is the most important step.
- Locate the Old Module: On most of these GM trucks and SUVs, the PCM is located in the engine bay on the driver’s side, often under or next to the battery tray or near the airbox.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that may need to be gently pried or squeezed. Once disconnected, unbolt the module from its mounting bracket.
- Install the New PCM: Mount your new, pre-programmed module in the same location. Secure the bolts, then firmly reconnect the wiring harnesses. You should hear a ‘click’ as they lock into place.
- Power Up: Reconnect the negative battery terminal and tighten it securely.
- Security Relearn Procedure: In many cases, you will need to perform a simple security relearn to sync the new PCM with your vehicle’s anti-theft system. This usually involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’ for 10 seconds, and repeating this cycle three times. Your vehicle should then start normally.
Guaranteed Fit for Your 2004 GM Vehicle
This 2004 GM Engine Computer is a direct replacement for service numbers 12586242, 19299226, 89017738 and broadcast codes including YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, YHTN. It is guaranteed to fit the following models:
- Buick Rainier (5.3L)
- Cadillac Escalade, ESV, EXT
- Chevrolet Avalanche 1500
- Chevrolet Silverado 1500, 2500, 3500 (Gasoline)
- Chevrolet SSR
- Chevrolet Suburban 1500, 2500
- Chevrolet Tahoe
- Chevrolet Trailblazer EXT (5.3L)
- GMC Envoy XL, XUV (5.3L)
- GMC Sierra 1500, 2500, 3500 (Gasoline)
- GMC Sierra Denali
- GMC Yukon, Yukon XL 1500, Yukon XL 2500
- Hummer H2
- Isuzu Ascender (5.3L)
From the Garage: A Customer’s Comeback Story
We had a customer, Mark, with a 2004 Sierra that he used for his contracting business. It started stalling randomly, making him late for jobs and costing him money. He’d replaced sensors and plugs, but nothing worked. He was ready to sell his beloved truck. We sent him one of these pre-programmed PCMs. He called back two days later, ecstatic. The 30-minute install had completely solved the problem. He said it felt like he got his old, reliable business partner back. That’s the feeling we aim for with every part we ship.
Frequently Asked Questions
How do I provide my VIN for programming?
It’s simple! After you complete your purchase, we will send you an email requesting your Vehicle Identification Number (VIN). Just reply to that email, and our technicians will handle the rest, ensuring the module is a perfect match for your vehicle’s configuration.
Will I need to do anything else after installing this part?
In most cases, you will need to perform a ‘Security Relearn Procedure’ to sync the new computer with your vehicle’s anti-theft system. This is a simple process that you can do yourself in about 30 minutes with just your car key. We include easy-to-follow instructions with your order.
Is this a plug-and-play solution?
Yes, because we program it to your VIN before shipping, it is designed to be a plug-and-play repair. It eliminates the need for an expensive trip to the dealership for programming. The only additional step is the potential security relearn.
My original part number is different. Will this still work?
Yes. As long as your original service number or broadcast code is on our cross-reference list (e.g., 19299226, YFKD, YFXL, etc.), this module is the correct, updated replacement for your vehicle.
What if this doesn’t fix my problem?
While this module corrects the most common electronic failures for these vehicles, we always recommend a proper diagnosis. If the part doesn’t solve your issue, it may point to a different problem (like wiring or another component). We stand by our products with a comprehensive warranty to ensure you are covered.