If you’re dealing with a 2009-2012 GMC Canyon that’s suddenly stalling, running rough, or refusing to start, the frustration is real. As a technician with over two decades of diagnostic experience, I’ve seen countless owners chase their tails replacing sensors and spark plugs, only to find the root cause was the Engine Control Module (ECM)—the brain of the vehicle. A faulty ECM can mimic a dozen other problems, making it one of the most misdiagnosed components in modern trucks.
This isn’t just a replacement part; it’s a direct solution. We are offering a genuine GM Engine Control Module, service number 12678512, that arrives at your doorstep fully programmed to your truck’s specific Vehicle Identification Number (VIN). This critical step, which we handle before shipping, means you can bypass the costly and time-consuming trip to a dealership. We load the latest GM-certified software, ensuring your engine operates with optimal performance, fuel efficiency, and emissions control, just as the factory intended.
Is Your Canyon Showing These Symptoms?
A failing ECM can manifest in various ways. In my shop, these are the most common complaints that lead back to a bad engine computer. If you’re experiencing any of these, a new module is the likely fix:
- âś” Unexplained Check Engine Light that won’t clear
- âś” Engine stalling or shutting off while driving
- âś” No-start or hard-start conditions
- âś” Noticeable drop in fuel economy
- âś” Rough or erratic idle
- âś” Communication loss codes (e.g., U0100)
- âś” Internal processor failure codes (e.g., P0601, P0606)
- âś” Transmission shifting problems or harsh shifts
Why a Pre-Programmed 2009-2012 Canyon ECM is the Smart Choice
Replacing an ECM isn’t like swapping an air filter. In the past, you’d have to buy the module, install it, and then have your vehicle towed to a dealer for programming. That process adds hundreds of dollars and days of downtime to the repair. Our solution eliminates that entire step. By providing us with your VIN during checkout, you receive a module that is truly plug-and-play. It’s the most efficient and cost-effective way to get your truck back on the road and running perfectly.
Case Study: The Ghost in the Machine
A customer brought in a 2011 Canyon 3.7L with an intermittent no-start condition that was driving him crazy. It would be fine for weeks, then suddenly refuse to crank. No codes were stored. We checked the battery, starter, and ignition switch—all tested perfectly. The problem was so random we couldn’t replicate it consistently. After keeping the truck for two days, I finally caught it in the act. The scan tool couldn’t communicate with the ECM. After letting it sit for an hour, it started right up. This pointed to a thermal failure inside the ECM; a hairline crack in a circuit board was separating when hot and reconnecting when cool. A new, programmed 2009-2012 Canyon ECM solved the problem permanently.
A Straightforward Guide to Installation
You don’t need to be a master mechanic to install this module. With basic hand tools, you can have this job done in under an hour. The ECM on the Canyon is typically located on the right-hand (passenger side) firewall in the engine bay.
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the ECM: Open the hood and find the module on the passenger-side firewall. It’s a metal box with several large electrical connectors.
- Disconnect the Connectors: Carefully unlatch and remove the wiring harness connectors. They have locking tabs, so don’t force them. Note their orientation.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New Module: Mount your new, pre-programmed ECM onto the bracket and secure the bolts.
- Reconnect Everything: Plug the wiring harness connectors back into the new module until they click securely into place. Reconnect the negative battery terminal.
- Final Step: Your vehicle may need to complete a security relearn procedure, which can often be done by cycling the key. In most cases, the truck will start right up, and you’re ready to go!
Verified Vehicle Compatibility
This module is a direct replacement for service number 12678512 and is interchangeable with part numbers 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, and 12630464. It fits a wide range of GM vehicles. Please confirm your model and engine below:
Cadillac: CTS (2009, 6.2L), DTS (2009-2011), SRX (2009, 4.6L), STS (2009-2010, 4.4L/4.6L), XLR (2009)
Chevrolet: Colorado (2009-2012, 2.9L/3.7L), Corvette (2009, ZR1), Trailblazer (2009, 6.0L)
GMC: Canyon (2009-2012, 2.9L/3.7L), Envoy (2009, 5.3L)
Hummer: H3 (2009-2010, 3.7L)
Saab: 9-7X (2009)
Frequently Asked Questions
Do I need to get this module programmed by a dealer?
No. We program the module to your vehicle’s VIN before we ship it. It arrives ready for installation, saving you the time and expense of a dealership visit.
What is a VIN and why do you need it?
The VIN (Vehicle Identification Number) is your car’s unique 17-digit serial number. It contains specific information about your vehicle’s options, engine, and security systems. We use it to load the exact correct software for your truck.
Where is the ECM located on my 2010 GMC Canyon?
On the 2009-2012 GMC Canyon and Chevy Colorado, the ECM is located in the engine compartment, mounted to the firewall on the passenger side.
My original part number is 12636659. Will this part work?
Yes. This module, 12678512, is the latest GM service replacement and is fully interchangeable with the older part numbers listed in the description, including 12636659.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the ECM (common codes P0601-P0606) or related communication errors, then yes, this part will resolve the issue. Always ensure your vehicle’s problem has been properly diagnosed.