Is Your 2009 GMC Envoy Running Rough?
If your vehicle is suffering from mysterious check engine lights, poor fuel economy, stalling, or a no-start condition, the culprit is often a failing Engine Control Module (ECM). As the central computer of your vehicle, the ECM is responsible for managing everything from fuel injection and ignition timing to transmission shifting and emissions control. When it begins to fail, it can cause a cascade of frustrating and difficult-to-diagnose problems. Don’t let a faulty computer keep your reliable truck off the road. This direct-fit replacement ECM, part number 12628993, is the definitive solution to restore your vehicle’s performance and dependability.
From the Diagnostic Bay
We had a 2009 Trailblazer (which uses this same module) come into the shop with an intermittent stalling issue that no one could figure out. The owner had replaced the fuel pump, crank sensor, and even the throttle body. The codes were all over the place. After confirming power and ground to the ECM were solid, we connected our scope and saw the injector driver signals were dropping out randomly. We installed one of these VIN-programmed modules, performed the security relearn, and the truck ran perfectly. It’s a classic case where chasing symptoms costs more than addressing the root cause: the vehicle’s brain was failing.
Symptoms of a Failing 2009 Envoy Engine Module
A failing ECM can manifest in numerous ways, often mimicking other component failures. If you’re experiencing any of the following, it’s time to consider your engine computer as the source of the problem:
- ✔ Unexplained Check Engine Light (CEL) illumination, often with communication-related trouble codes (U-codes).
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ A complete no-start condition where the engine cranks but will not fire.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Misfire codes that persist even after replacing spark plugs, coils, and injectors.
- ✔ Intermittent loss of power to other electronic components.
The Plug-and-Play Solution
What sets this module apart is our professional programming service. We don’t just send you a generic part; we ensure it’s ready for your specific vehicle. When you place your order, you will provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). Our technicians will then use this information to load the latest, most stable GM-certified software directly onto the module. This critical step ensures that the computer is perfectly matched to your Envoy’s specific engine, transmission, and factory options. This eliminates the need for an expensive trip to the dealership for programming, saving you time and money.
This module is a direct replacement for a wide range of GM vehicles and is interchangeable with the following service numbers: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. Please verify the part number on your original module or consult our comprehensive fitment list below to ensure compatibility.
Verified Vehicle Fitment
This Engine Control Module is compatible with a wide array of General Motors vehicles. Please check your specific model and engine option below:
- ENVOY 09 Electronic Control Module; (LH engine), 5.3L
- TRAILBLAZER 09 Electronic Control Module; (LH engine), 6.0L
- SAAB 9-7X 09 Electronic Control Module; (LH engine)
- COLORADO 09-12 Electronic Control Module; (RH firewall), 2.9L, 3.7L
- CANYON 09-12 Electronic Control Module; (RH firewall), 2.9L, 3.7L
- HUMMER H3 09-10 Electronic Control Module; (RH firewall)
- CORVETTE 09 Electronic Control Module; (RH engine compartment), ZR1
- CTS 09 Electronic Control Module; (RH front engine compartment), 6.2L
- STS 09-10 Electronic Control Module; (LH frame rail), 4.4L, 4.6L
- SRX 09 Electronic Control Module; (LH engine compartment), 4.6L
- XLR 09 Electronic Control Module; (RH front engine compartment)
- DTS 09-11 Electronic Control Module
- LUCERNE 09-11 Electronic Control Module; (lower part of air cleaner box), 4.6L
Frequently Asked Questions
Why do I need to provide my VIN?
Your vehicle’s VIN is essential for us to program the module with the correct software for your specific engine, transmission, and factory-installed options. This ensures seamless integration and proper function without needing a trip to the dealer.
Is this part difficult to install?
The physical installation is straightforward for someone with basic mechanical skills. It typically involves disconnecting the battery, unplugging the electrical connectors, and unbolting the old module. After installing the new one, you may need to perform a simple security relearn procedure, which can usually be done without special tools. Instructions are widely available online.
Will this fix my check engine light?
If the check engine light is caused by a faulty ECM or an internal processor error, this replacement module will resolve the issue. However, if the light is on due to a separate sensor or component failure (like an oxygen sensor or catalytic converter), that part will still need to be addressed.
Is this a new or used part?
This is a high-quality, tested, and verified used OEM component. Each unit is inspected and then programmed with the latest GM software for your vehicle to ensure it meets or exceeds original factory performance standards.
What if I have questions after my purchase?
Our team of automotive experts is here to help. If you have any questions during the installation process or need assistance with diagnostics, please don’t hesitate to contact our customer support.