Restore Peak Performance and Reliability to Your Truck
There’s nothing more frustrating than a vehicle you can’t depend on. If your 2004 Sierra Denali—or another compatible GM truck or SUV—is suffering from baffling electrical gremlins, poor performance, or a dreaded no-start condition, the Powertrain Control Module (PCM) is often the culprit. This isn’t just a part; it’s the central nervous system of your vehicle. When it fails, it can disrupt everything. This replacement PCM, part number 12586242, is the definitive solution to get your truck back on the road, running with the smooth, predictable power you remember.
We take the guesswork and complexity out of the repair. Each module is meticulously programmed with the latest official GM software updates, tailored specifically to your vehicle’s unique Vehicle Identification Number (VIN). This means no expensive trips to the dealership for flashing, no complicated tools required. It’s designed to be a direct, plug-and-drive fix that restores function and gives you back the confidence of a worry-free drive.
An Old Pro’s Diagnostic Tale
I once had a 2004 Yukon XL in the bay that was driving the owner crazy. It would randomly stall at stoplights, but never threw a consistent code. We checked the fuel pump, ignition system, and all the usual suspects. After hours of chasing ghosts, we finally swapped in a known-good PCM. The truck fired up and ran like a top. The original PCM had an internal intermittent fault that was impossible to pin down with a scanner. It’s a reminder that sometimes, the brain itself is the source of the confusion, and a quality replacement is the only true fix.
Is Your Vehicle Showing These Symptoms?
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, this module is likely the solution you need:
- ✔ Persistent Check Engine Light with communication-related Diagnostic Trouble Codes (DTCs) like P0601, P0602, P0606.
- ✔ Unexplained stalling or rough, erratic idling.
- ✔ Complete no-start condition where the engine cranks but won’t fire.
- ✔ Harsh or incorrect transmission shifting patterns.
- ✔ A sudden, noticeable drop in fuel economy.
- ✔ Inaccurate readings from gauges on the instrument cluster.
Guided Installation for Your 2004 Sierra Denali PCM
Replacing the PCM is a straightforward job you can tackle with basic hand tools. Our pre-programming makes it even simpler. Follow these steps for a confident installation.
- Safety First: Always begin by disconnecting the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the Module: On most trucks like the Sierra, Silverado, and Yukon, the PCM is located on the driver’s side, in the engine bay, under or next to the battery tray.
- Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that may need to be gently pried up. Once disconnected, unbolt the module from its mounting bracket and remove it.
- Install the New PCM: Mount your new, pre-programmed PCM onto the bracket. Reconnect the electrical harnesses, ensuring they click securely into place.
- Final Steps: Reconnect the negative battery terminal. The vehicle may need to perform a security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes. Start the engine and enjoy a restored ride!
Guaranteed Fitment for Your Vehicle
This module is a direct replacement for service numbers 12586242, 19299226, 89017738 and various service IDs including YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, YHTN. It is confirmed to fit the following 2004 models:
- 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)
- Buick Rainier (5.3L)
Note: After purchase, please provide your VIN to ensure we program the module perfectly for your vehicle’s specific configuration.
Frequently Asked Questions
Is this PCM ready to install right out of the box?
Yes! We program the computer to the specific VIN you provide, including the latest GM software updates. In most cases, it is a plug-and-drive installation, though some vehicles may require a simple security relearn procedure that you can do yourself in minutes.
How do I provide my VIN for programming?
After you complete your purchase, you can send us a message with your 17-digit Vehicle Identification Number (VIN). We cannot ship your order until we receive this information, as the programming is essential for the part to work correctly.
Where is the PCM located on my 2004 Sierra Denali?
On the 2004 GMC Sierra Denali, the PCM is typically found in the engine compartment on the driver’s side, mounted near the battery, often underneath the battery tray itself.
Do I need to send my old computer back?
No core charge or return is required for this part. You can keep your old module or dispose of it responsibly.
What if my original part has a different service number?
This module replaces a wide range of service numbers, including 12586242, 19299226, 89017738, and many more listed in the description. As long as your vehicle is on the compatibility list, we will program this unit to function perfectly as a replacement.