Restore Peak Performance to Your GM Vehicle
Is your vehicle suffering from baffling electrical gremlins, poor fuel economy, or a frustrating no-start condition? The Engine Control Module (ECM), often called the vehicle’s brain, is the central command for all critical engine functions. When it fails, it can cause a cascade of problems that are often difficult to diagnose. This isn’t just an inconvenience; it affects your vehicle’s reliability, safety, and performance. As a technician with over two decades of experience, I’ve seen firsthand how a faulty ECM can sideline a perfectly good truck or car.
This replacement Engine Control Module, part number 12630464, is the definitive solution for a wide range of GM vehicles. The biggest hurdle with ECM replacement has always been the expensive and time-consuming programming required at a dealership. We eliminate that step entirely. By providing your Vehicle Identification Number (VIN) at checkout, you receive a module that is professionally flashed with the latest official GM software updates specific to your vehicle. It arrives at your door ready for installation, saving you hundreds of dollars and significant downtime. This is the most direct path to getting your vehicle running correctly again.
A Technician’s Notebook: The Ghost in the Machine
I remember a 2010 Chevy Colorado that came into the shop with a textbook ‘ghost’ problem. The owner had replaced the battery, alternator, and multiple sensors trying to chase down an intermittent stalling issue and a check engine light that would come and go. The codes were all over the place—U0100 (Lost Communication with ECM), P0606 (ECM Processor Fault), and random sensor circuit faults. After verifying all the wiring and grounds were solid, we focused on the ECM. A faulty processor was causing it to send erratic signals, making other components appear faulty. Installing a correctly programmed 2009 Envoy Engine Module (the same family of ECMs) resolved every single issue instantly. It’s a classic case where the root cause is the central computer, not the parts it controls.
Is Your Vehicle Showing These Symptoms?
A failing ECM can manifest in many ways. If you’re experiencing any of the following, your engine computer is a likely culprit. This is especially true if you’re seeing communication-related Diagnostic Trouble Codes (DTCs).
- ✔ Check Engine Light is on with codes like P0601, P0606, or U-series communication codes.
- ✔ Engine cranks but refuses to start.
- ✔ Noticeable drop in fuel efficiency for no apparent reason.
- ✔ Rough idling, stalling, or hesitation during acceleration.
- ✔ Automatic transmission shifts erratically or harshly.
- ✔ Misfires or poor engine performance that isn’t solved by new plugs or coils.
- ✔ Complete loss of communication with diagnostic scan tools.
A Straightforward Guide to Installation
Installing your new 2009 Envoy Engine Module is a job most DIYers with basic tools can handle. Our pre-programming service makes it a true plug-and-play process, but always follow proper safety procedures.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the ECM: The location varies by model (see fitment list below). It’s typically on the firewall, in the engine bay on a fender, or near the air cleaner box.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old module. These usually have a locking tab or lever that needs to be released. Do not force them.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed ECM in the same location and secure it with the bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn (If Necessary): While most vehicles will start immediately, some GM models require a simple key-cycle security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your vehicle’s specific procedure if needed.
Verified Vehicle Compatibility
This module is a direct replacement for a broad range of General Motors vehicles and is interchangeable with service numbers 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. Please confirm your model and engine below:
CADILLAC DTS 09-11
CADILLAC SRX 09 (4.6L)
CADILLAC STS 09 (4.4L, 4.6L)
CADILLAC STS 10 (4.6L)
CADILLAC XLR 09
CHEVROLET COLORADO 09-12 (2.9L, 3.7L)
CHEVROLET CORVETTE 09 (ZR1)
CHEVROLET TRAILBLAZER 09 (6.0L)
GMC CANYON 09-12 (2.9L, 3.7L)
GMC ENVOY 09 (5.3L)
HUMMER H3 09-10 (3.7L)
BUICK LUCERNE 09-11 (4.6L)
SAAB 9-7X 09
Frequently Asked Questions
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle all the programming before shipping. You just need to provide your VIN during checkout. The module arrives ready to install.
What is a VIN and where do I find it?
The VIN is your vehicle’s unique 17-digit serial number. You can find it on your driver’s side dashboard (viewable through the windshield), on the driver’s door jamb sticker, or on your vehicle’s registration and insurance documents.
Is this part difficult to install?
For most individuals with basic mechanical skills, this is a straightforward replacement. It involves disconnecting the battery, unplugging the old module, unbolting it, and reversing the process with the new one. No special tools are typically required.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of your original ECM (like codes P0601 or P0606), then yes, this part is designed to correct that specific problem. It’s always best to have the codes read to confirm the diagnosis.
What if my original part number is different?
This module is a direct replacement for several service numbers, including 12636659, 12628993, and others listed above. As long as your vehicle is on the compatibility list, this module will function correctly.
What is a security relearn procedure?
On some GM vehicles, the anti-theft system needs to recognize the new ECM. This is usually a simple process of cycling the key in the ignition. It does not require a scan tool. We can provide general instructions if needed.