Restore Peak Performance and Reliability to Your Truck
Is your 2004 Hummer H2, Silverado, or Sierra plagued by a persistent Check Engine Light, rough idling, or frustrating no-start conditions? These are classic signs that the very brain of your engine, the Powertrain Control Module (PCM), is failing. Don’t let electrical gremlins keep you off the road. This direct-replacement PCM, part number 12586242, is the definitive solution to restore your vehicle’s power, efficiency, and dependability. We take the guesswork out of the repair by pre-programming the module to your vehicle’s specific VIN, ensuring a seamless, plug-and-play installation.
From the Mechanic’s Bay
I once had a customer with a 2004 Sierra 1500 who had spent hundreds of dollars replacing O2 sensors and the MAF sensor, but the lean codes and poor mileage just wouldn’t go away. The issue wasn’t the sensors themselves; it was a faulty PCM providing incorrect data. After installing a VIN-programmed module like this one, all the codes vanished, and the truck ran better than it had in years. Sometimes, you have to go straight to the source of the problem.
Warning Signs and How to Overcome Them
A failing PCM can manifest in numerous ways. If you’re experiencing any of the following, this module is your solution for a confident and lasting repair:
- ✔ Persistent Check Engine Light (CEL) with various DTCs
- ✔ Engine stalling, stumbling, or hesitating during acceleration
- ✔ Unexplained drop in fuel economy
- ✔ Harsh or erratic transmission shifting
- ✔ Complete no-start or intermittent starting issues
- ✔ Communication error codes (e.g., U0100)
- ✔ False sensor readings even after replacing the sensors
Guided Installation for Your 2004 HUMMER H2 PCM
We’ve made this repair as straightforward as possible. With the programming already handled, you can get this done in your own driveway with basic tools. Here’s a simple guide to get you back on the road:
- Safety First: Begin by disconnecting the negative terminal on your vehicle’s battery to prevent any electrical shorts.
- Locate the Old Module: On most of these GM trucks and SUVs, the PCM is located in the engine bay, either on the driver’s side next to the airbox or under the battery tray.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that need to be released. Once disconnected, unbolt the module from its mounting bracket.
- Install the New PCM: Mount your new, pre-programmed module in the same location. Securely reconnect the wiring harnesses, ensuring they click into place.
- Power Up: Reconnect the negative battery terminal. The vehicle may require a simple security relearn procedure (often just turning the key to ‘On’ for 10-15 minutes), and you’ll be ready to start the engine and enjoy a smooth, worry-free drive.
Tailored Fit for Your Ride
This module is a guaranteed fit for a wide range of 2004 GM vehicles. Please verify your service number matches one of the following: 12586242, 19299226, 89017738, YFKD, YFKF, YFKH, YFKJ, YFKX, YFXL, YFXM, YFXN, YFXP, or YHTN.
Compatible models include:
- 2004 HUMMER H2
- 2004 Cadillac Escalade, ESV, EXT
- 2004 Chevrolet Avalanche 1500
- 2004 Chevrolet Silverado & Sierra 1500, 2500, 3500 (Gasoline)
- 2004 Chevrolet Suburban & Yukon XL 1500, 2500
- 2004 Chevrolet Tahoe & Yukon
- 2004 Chevrolet SSR
- 2004 GMC Envoy XL & XUV (5.3L)
- 2004 Chevrolet Trailblazer EXT (5.3L)
- 2004 Buick Rainier (5.3L)
- 2004 Isuzu Ascender (5.3L)
Frequently Asked Questions
Do I need to do any programming or flashing myself?
Absolutely not. We handle all the programming for you before shipment. Simply provide your vehicle’s VIN during checkout, and we’ll flash the module with the latest GM-certified software for your specific vehicle. It arrives ready to install.
Where is the PCM located on my 2004 GM truck?
The location can vary slightly. On models like the Silverado, Sierra, and Hummer H2, it’s typically found in the engine compartment on the driver’s side, mounted under the battery tray. On Trailblazer/Envoy platforms, it’s often located next to the air filter box.
What is a security relearn, and is it difficult?
A security relearn, or ‘anti-theft relearn,’ syncs the new PCM with your vehicle’s security system. It’s very simple and requires no tools. The most common method is to turn the key to the ‘ON’ position (without starting the engine) for 10-12 minutes, then turn it ‘OFF’ for 30 seconds, and repeat two more times. After the third cycle, the vehicle should start normally.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM also controls transmission functions, including shift points and line pressure. If your module is failing, it can cause erratic shifting. A new, correctly programmed PCM often resolves these issues, leading to a much smoother driving experience.
What information do you need from me to program the module?
All we need is your vehicle’s 17-digit Vehicle Identification Number (VIN). You can typically find this on your driver’s side dashboard (visible through the windshield), on the driver’s door jamb sticker, or on your vehicle’s registration and insurance documents.