Restore Peak Performance to Your HUMMER H2
If your 2003-2007 HUMMER H2 is suffering from frustrating issues like a persistent check engine light, erratic shifting, stalling, or a no-start condition, a failing Powertrain Control Module (PCM) is often the culprit. As the central computer of your vehicle, the PCM manages everything from fuel mixture and ignition timing to transmission shift points. When it fails, the symptoms can be confusing and widespread. This replacement 2003-2007 HUMMER H2 PCM is the reliable, straightforward solution to get your truck back to running like it should.
The biggest headache with replacing a PCM has always been the expensive and time-consuming trip to the dealership for programming. We eliminate that step entirely. Before we ship your module, our expert technicians will flash it with the latest official GM software updates, specifically matched to your vehicle using the VIN you provide. This ensures perfect compatibility and function right out of the box, saving you time and hundreds of dollars in programming fees.
From the Diagnostic Bay: A Costly Misdiagnosis
A customer brought in a 2005 HUMMER H2 with a nasty, intermittent stalling problem and a check engine light. Another shop had already replaced the throttle body and mass airflow sensor, but the problem persisted. After hooking up my scan tool, I noticed communication errors (U-codes) alongside a P0601 (Internal Control Module Memory Check Sum Error). This combination is a classic red flag for a failing PCM. The processor was failing, sending faulty signals that made other components appear to be the problem. A new, correctly programmed PCM fixed it instantly. This story highlights why addressing the vehicle’s ‘brain’ first can save you from replacing perfectly good parts.
Is Your H2 Showing These Signs of a Failing PCM?
- ✔ Check Engine Light is on with codes like P0601, P0606, or U0100.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ The vehicle stalls unexpectedly while driving or at idle.
- ✔ Multiple, unrelated sensor codes appearing at the same time.
A Straightforward Guide to Installation
Replacing the PCM on your HUMMER H2 is a job most DIYers can handle with basic tools. This module is typically located in the engine bay on the driver’s side, under the battery tray.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Access the Module: You will likely need to remove the battery and the battery tray to gain clear access to the old PCM.
- Disconnect: Carefully unplug the electrical connectors from the old module. There are typically two or three large connectors with locking tabs. Be gentle to avoid damaging the pins or clips.
- Swap the Part: Unbolt the old PCM from its mounting bracket and install the new one in its place.
- Reconnect: Firmly plug the electrical connectors into your new, pre-programmed PCM. You should hear a ‘click’ as they lock into place.
- Final Steps: Reinstall the battery tray and the battery, then reconnect the negative battery terminal. In some cases, a security relearn procedure may be necessary, which can be done without special tools.
Verified Fitment for Your GM Truck or SUV
This module is a direct replacement for part number 12589463 and is compatible with service numbers 89017750, 12582605, 12602802, 89017734, and 28042802. It fits a wide range of GM vehicles, including:
- HUMMER H2: 2003, 2004, 2005, 2006, 2007
- Cadillac Escalade, ESV, EXT: 2003-2006
- Chevrolet Avalanche, Silverado, Suburban, Tahoe, SSR, Trailblazer EXT: 2003-2007 (see fitment list for specific options)
- GMC Sierra, Yukon, Envoy XL: 2003-2007 (see fitment list for specific options)
- Isuzu Ascender: 2003
Please verify your vehicle in the detailed fitment list or contact us with your VIN to confirm compatibility.
Frequently Asked Questions
Do I need to program this PCM?
No! This is the main benefit of our service. We program the module to your vehicle’s specific VIN before shipping it. It arrives ready for installation.
What do you need from me after I order?
After you complete your purchase, you must provide us with your vehicle’s 17-digit VIN (Vehicle Identification Number). We cannot ship the part until we have this information to program it correctly.
Where do I find my VIN?
Your VIN is located on the driver’s side of the dashboard (visible through the windshield), on the driver’s side door jamb sticker, and on your vehicle’s registration and insurance documents.
What if my original part number is different but on the compatible list?
GM often uses several interchangeable service numbers for the same part. As long as your original number is on our compatibility list (e.g., 12602802, 89017750), this module is the correct replacement for your vehicle.
Will I need to perform a security relearn procedure?
On many GM vehicles of this era, a security relearn (also known as a Passlock or anti-theft relearn) is required after swapping the PCM. This procedure syncs the new module with your vehicle’s anti-theft system. It’s a simple process that typically involves turning the key to the ‘ON’ position for 10-15 minutes, three times in a row. Instructions are readily available online for your specific model.