Is Your Hummer H2 Running Rough, Stalling, or Refusing to Start?
There’s nothing more frustrating than when a vehicle as capable as your Hummer H2 is sidelined by electrical problems. If you’re dealing with a persistent check engine light, erratic transmission shifting, poor fuel economy, or a no-start condition, the culprit is often a failing Powertrain Control Module (PCM). As the central computer for your engine and transmission, its health is critical to your truck’s performance and reliability. Over my 20+ years in the shop, I’ve seen countless GM trucks and SUVs, including the H2, develop these exact issues due to a faulty PCM.
Expert Pro Tip from a 20-Year Technician
Before you condemn your old PCM, take a moment to inspect the wiring harness connectors that plug into it. They are located under the battery tray and are susceptible to corrosion from battery acid fumes or moisture. Use a small brush and electrical contact cleaner to ensure the pins and sockets are spotless. A poor connection can mimic the symptoms of a failed module. I’ve saved customers hundreds of dollars with this simple 5-minute check.
The Direct-Fit Solution: A Programmed 2003-2007 Hummer H2 PCM
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We take the guesswork and expensive dealer trips out of the equation. When you order, simply provide us with your vehicle’s VIN. We will then flash this module with the latest, most stable GM factory software specific to your Hummer H2. This ensures all parameters for the engine, transmission, and emissions systems are perfectly matched to your vehicle’s original specifications.
Key Benefits of This Programmed PCM:
- โ VIN-Programmed for Your Vehicle: Arrives flashed with the latest GM software updates for your specific Hummer H2.
- โ True Plug-and-Play Installation: No additional programming or security relearn procedures are required. Just install it and start your engine.
- โ Solves Common Failure Symptoms: A reliable fix for issues like random stalling, harsh shifting, false sensor codes, and no-start conditions.
- โ Restores Original Performance: Get your H2’s power, fuel efficiency, and smooth operation back to factory standards.
- โ Wide Compatibility: This module, part number 12589463, also replaces several other service numbers, ensuring a perfect match.
Simple Installation Guide: Get Back on the Road Fast
You don’t need to be a master mechanic to install this PCM. The process is straightforward and can be done with basic hand tools.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Access the Module: On the Hummer H2, the PCM is located in the engine bay on the driver’s side, typically under the battery and its tray. You will need to remove the battery to gain access.
- Disconnect the Old PCM: Carefully unplug the electrical connectors from the old module. There are usually release tabs that need to be pressed or lifted.
- Remove the Old Unit: Unbolt the old PCM from its mounting bracket.
- Install the New PCM: Mount your new, pre-programmed PCM and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock into place.
- Final Steps: Reinstall the battery tray and the battery. Reconnect the negative battery terminal. Your Hummer H2 is now ready to start.
Guaranteed Fitment & Part Number Information
This module is a direct replacement for units with part number 12589463 and is also fully compatible with the following service numbers: 89017750, 12582605, 12602802, 89017734, and 28042802. Please verify the number on your existing module to ensure compatibility. While this is listed for the Hummer H2, it also fits a wide range of other GM trucks and SUVs from 2003-2007, including the Silverado, Sierra, Tahoe, and Escalade, as detailed in the fitment list.