Restore Peak Performance to Your Hummer H3
Is your 2009 or 2010 Hummer H3 suffering from frustrating and unpredictable engine problems? Issues like stalling, rough idling, a persistent Check Engine Light, or a complete failure to start can often be traced back to a failing Engine Control Module (ECM). The ECM is the brain of your vehicle’s engine, and when it malfunctions, it can disrupt everything from fuel delivery to ignition timing. This replacement Engine Control Module, part number 12628993, is the definitive solution to get your rugged H3 back on the road and running like new.
We take the guesswork and hassle out of the replacement process. Unlike a generic module from a parts store, this unit is specifically programmed for your vehicle before it ships. Simply provide us with your Hummer’s Vehicle Identification Number (VIN) during checkout, and our technicians will flash the module with the latest, most stable software updates directly from GM. This ensures perfect compatibility and function, eliminating the need for an expensive trip to the dealership for programming.
Common Symptoms of a Failing Hummer H3 ECM
If you’re experiencing any of the following issues, a faulty ECM could be the culprit. Proper diagnosis is always recommended, but these are the classic signs that your engine’s computer is in distress:
- ✔ Check Engine Light: The light is on, and you may have codes related to module communication, sensor circuits, or processor faults.
- ✔ Engine Stalling or Misfiring: The engine may stall unexpectedly, run rough, or misfire, especially under load.
- ✔ No-Start Condition: The engine cranks but refuses to start, indicating a potential loss of fuel or spark control from the ECM.
- ✔ Poor Fuel Economy: A malfunctioning ECM can’t properly manage the air-fuel mixture, leading to a noticeable drop in MPG.
- ✔ Inconsistent Performance: You might notice hesitation during acceleration, loss of power, or erratic transmission shifting behavior.
- ✔ Communication Errors: A diagnostic scan tool may be unable to communicate with the ECM, a clear sign of an internal failure.
From the Diagnostic Bay
We had a 2009 H3 come into the shop with a ghost of a problem. The owner complained of random stalling at traffic lights, but it would always start right back up. We checked the fuel pump, sensors, and wiring, but everything tested fine. There were no hard codes stored, just a history of ‘lost communication’ events. On a hunch, we monitored the ECM’s live data stream and noticed the processor would occasionally drop out for a split second—just long enough to kill the engine. We installed a pre-programmed 2009-2010 Hummer H3 ECM, and the problem was solved instantly. It’s a classic case where the central component was causing intermittent issues that mimicked other failures.
Why Choose Our Pre-Programmed 2009-2010 Hummer H3 ECM?
This isn’t just a part; it’s a complete, ready-to-install solution. The critical advantage is the VIN-specific programming. Your Hummer H3 has unique settings for its engine, transmission, and options package. Our process ensures the ECM we send you is a perfect digital match for your vehicle’s original configuration. This plug-and-play approach saves you hundreds of dollars in dealership programming fees and gets your vehicle repaired faster.
Simple Installation Process
Replacing the ECM is a straightforward job for a DIY mechanic or any professional technician. After installation, you may need to perform a simple security relearn procedure (also known as a key relearn) to sync the new ECM with your vehicle’s anti-theft system. This procedure typically takes about 30 minutes and can be done without any special tools. Instructions are widely available online or in your vehicle’s service manual.
Broad Compatibility
This module is a direct replacement for several GM service numbers, ensuring wide-ranging compatibility. This part is interchangeable with the following numbers: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. It also fits a variety of other GM vehicles, including select models of the Chevrolet Colorado, GMC Canyon, Cadillac CTS, and more, as detailed in the fitment guide.
Frequently Asked Questions
Do I need to have this ECM programmed by a dealer?
No. We handle the programming for you before we ship the part. Just provide your vehicle’s 17-digit VIN at checkout, and it will arrive ready to install with the latest GM software for your specific vehicle.
What is a security relearn procedure?
It’s a simple process that syncs the new ECM to your vehicle’s anti-theft system. It usually involves a sequence of turning the ignition key on and off for set periods. You can do this yourself in your driveway without any special tools.
Where do I find my VIN?
Your VIN can be found on a metal plate on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, or on your vehicle’s registration and insurance documents.
Is this a brand new part?
This is a high-quality, fully tested OEM-grade replacement part, guaranteed to meet or exceed original factory specifications. Each unit is inspected and programmed to ensure reliable, long-lasting performance.
Will this fix my check engine light?
If the check engine light and associated symptoms are caused by a faulty ECM, this part will resolve the issue. However, we always recommend a proper diagnosis by a qualified technician to confirm the ECM is the point of failure before ordering.