Restore Peak Performance and Reliability to Your GM Vehicle
Is your vehicle suffering from a persistent check engine light, erratic performance, or a frustrating no-start condition? As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Engine Control Module (ECM) can be the hidden culprit behind a host of baffling issues. The ECM is the brain of your vehicle, managing everything from fuel injection and ignition timing to transmission shifts. When it falters, the entire system suffers. This direct-replacement 2009 Envoy Engine Module is the definitive solution to restore your vehicle’s factory performance and get you back on the road with confidence.
What sets this module apart is our professional, VIN-specific programming service. Before this ECM ever leaves our facility, we flash it with the latest, most stable software updates directly from GM, tailored precisely to your vehicle’s Vehicle Identification Number (VIN). This critical step ensures seamless communication between all vehicle systems and eliminates the need for an expensive trip to the dealership for programming. You receive a component that is truly ready for installation right out of the box.
A Technician’s Notebook
I recently had a 2009 Trailblazer with the 6.0L in my bay that was a real head-scratcher. The owner complained of random stalling at stoplights and an intermittent no-start, but it never stored any consistent trouble codes. We checked fuel pressure, ignition components, and even the crank sensor—all were fine. On a hunch, I monitored the ECM data stream and noticed the 5-volt reference signal would occasionally drop out for a split second, just before the engine would die. This pointed to an internal failure in the original ECM. We installed one of these pre-programmed modules, and the problem was solved instantly. It’s a classic example of how a faulty 2009 Envoy Engine Module can mimic other, more common failures.
Is Your GM Vehicle Showing These Red Flags?
A failing ECM can manifest in numerous ways. If you’re experiencing any of the following, a replacement module is often the correct diagnosis:
- ✔ Check Engine Light is on with communication-related or internal processor fault codes (e.g., P0601, P0606, U0100).
- ✔ Engine cranks but will not start.
- ✔ Poor fuel economy and engine performance, including hesitation or misfires.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Seemingly unrelated warning lights on the instrument cluster.
- ✔ Intermittent stalling for no apparent reason.
Straightforward Installation Guide
Installing your new ECM is a manageable task for a confident DIYer. Follow these steps carefully for a smooth replacement.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow all systems to power down completely.
- Locate the ECM: On most of these vehicles, the ECM is found in the engine bay, often on the firewall, inner fender, or near the air filter box. Refer to your vehicle’s service manual for the exact location.
- Disconnect Connectors: Carefully release the locking tabs on the electrical connectors and pull them straight out from the module. Never force them. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed ECM securely. Reconnect the electrical connectors, ensuring they click firmly into place.
- Reconnect Battery: Reattach the negative battery terminal. Your vehicle is now ready to start. It may run slightly differently for the first few drive cycles as it completes its internal relearn procedures.
Verified Vehicle Compatibility
This ECM, part number 12636659, is a direct replacement for a wide range of GM vehicles. It is interchangeable with service numbers 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. Please verify your model and engine below:
LUCERNE 09-11 (4.6L, lower air cleaner box)
Cadillac:
CTS 09 (6.2L, RH front engine compartment)
DTS 09-11
SRX 09 (4.6L, LH engine compartment)
STS 09 (4.4L or 4.6L, LH frame rail)
STS 10 (4.6L, LH frame rail)
XLR 09 (RH front engine compartment, ID 12636659 or 12625453)
Chevrolet:
COLORADO 09 (All Engines)
COLORADO 10-12 (2.9L or 3.7L)
CORVETTE 09 (ZR1, RH engine compartment)
TRAILBLAZER 09 (6.0L, LH engine)
GMC:
CANYON 09 (All Engines)
CANYON 10-12 (2.9L or 3.7L)
ENVOY 09 (5.3L, LH engine)
Hummer:
HUMMER H3 09-10 (All Engines)
Saab:
SAAB 9-7X 09 (LH engine)
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential for us to program the module with the exact software and calibrations your specific vehicle requires. This ensures perfect compatibility and function, just like a part from the dealer.
Is this ECM really ‘plug and play’?
Yes. Because we pre-program it to your VIN, no further programming or flashing is required after installation. In some cases, a security or crank position sensor relearn may be needed, which can be done with many common scan tools or by following a specific drive cycle.
Will this fix my check engine light?
If the check engine light is caused by an internal ECM failure (like codes P0601-P0606) or a fault the ECM is responsible for, then yes, this will resolve the issue. Always ensure you have performed a proper diagnosis to confirm the ECM is the root cause.
What if I have a different part number on my original module?
This module is a direct replacement for several service numbers, including 12639300, 12639300, 1263605, and more. As long as your vehicle is on our compatibility list, this part will function correctly.
Is this a new or used part?
This is a high-quality, tested replacement component that has been verified for full functionality and programmed with the latest GM software for your vehicle.