Restore Peak Performance to Your Vehicle’s Engine
Is your GMC Envoy, Trailblazer, or other compatible GM vehicle suffering from mysterious and frustrating issues? Stalling, rough idling, a persistent Check Engine Light, or a complete failure to start can often be traced back to a single, critical component: the 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 fails, the entire system can be compromised, leading to poor performance, reduced fuel economy, and potential damage to other engine components.
This replacement Engine Control Module, part number 12639300, is the definitive solution to get your vehicle running like new again. We take the guesswork and hassle out of the repair process. Unlike a generic module from a parts store or a salvage yard, each unit we ship is professionally programmed with the latest GM-certified software updates specifically for your vehicle. All we need is your Vehicle Identification Number (VIN) at checkout. This ensures that when the part arrives, it’s a true plug-and-play solution, ready for installation without requiring expensive trips to the dealership for programming.
From the Diagnostic Bay
We had a 2009 Trailblazer come into the shop with a complaint that stumped two other mechanics. The owner described intermittent stalling at stoplights and a strange hesitation under acceleration, but there were no consistent trouble codes stored in the system. We checked fuel pressure, scanned for vacuum leaks, and tested the ignition system—all checked out fine. On a hunch, we monitored the live data stream from the ECM and noticed erratic readings from the throttle position sensor, even though the sensor itself tested good. The culprit was a failing processor inside the original ECM, causing it to misinterpret sensor data. After installing one of our pre-programmed modules, the Trailblazer ran flawlessly. It’s a perfect example of how a faulty ECM can create ghost-like symptoms that are nearly impossible to trace without replacing the unit.
Symptoms of a Failing Engine Control Module
- ✔ Check Engine Light: The most common indicator, often with codes related to multiple, unrelated sensors.
- ✔ Engine Stalling or Misfiring: The engine may stall unexpectedly or run rough due to incorrect fuel and spark commands.
- ✔ No-Start Condition: The ECM may fail to activate the fuel pump or ignition coils, preventing the engine from starting at all.
- ✔ Poor Performance & Fuel Economy: Inefficient engine operation managed by a faulty ECM can lead to a noticeable drop in power and an increase in fuel consumption.
- ✔ Shifting Problems: In many vehicles, the ECM works with the Transmission Control Module (TCM) to ensure smooth shifts. A bad ECM can cause harsh or erratic shifting.
- ✔ Intermittent Issues: Problems that come and go with temperature changes are a classic sign of failing electronic components within the module.
Why Choose Our Programmed 2009 Envoy Engine Module?
Getting your vehicle back on the road shouldn’t be complicated. Our process is designed for both professional technicians and savvy DIYers. By programming the module to your VIN before shipping, we eliminate the most difficult step of the replacement process. This 2009 Envoy Engine Module is meticulously inspected and prepared to meet or exceed original equipment standards. It’s a reliable, cost-effective alternative to expensive dealership parts. You receive a component that is ready to restore your vehicle’s original drivability, emissions compliance, and overall function.
Guaranteed Fitment & Compatibility
This module is a direct replacement for a wide range of General Motors vehicles. Please verify that your vehicle is on the list below. This unit is interchangeable with the following GM service numbers: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512.
This part will fit these makes and models with these options:
- ✔ 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)
- ✔ CANYON 09-12 Electronic Control Module; (RH firewall)
- ✔ 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
- ✔ SRX 09 Electronic Control Module; (LH engine compartment), (4.6L)
- ✔ STS 09-10 Electronic Control Module; (LH frame rail), 4.4L or 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
Do I need to do any programming after I receive this ECM?
No. This module comes fully programmed to your vehicle’s specific VIN. It is ready for installation right out of the box. In some cases, a security or CASE relearn procedure may be required, which can be done with a capable scan tool.
Where do I provide my VIN?
Please enter your 17-digit Vehicle Identification Number (VIN) in the notes section during checkout. We cannot program and ship your module without it.
Is this a simple part to install myself?
For someone with moderate mechanical experience, it is a straightforward installation. The most important step is to disconnect the vehicle’s battery before removing the old module and installing the new one. The module is typically located in the engine bay and is secured with a few bolts and electrical connectors.
What if my original part number is not 12639300?
This module is a direct replacement for several service numbers, including 12636659, 12628993, and others listed above. As long as your vehicle model and year are on our compatibility list, this module will function correctly once programmed to your VIN.
What is your warranty policy?
We stand behind our products with a comprehensive warranty. Please see the warranty tab on this product page for full details regarding coverage and duration.