Restore Peak Performance and Reliability to Your GM Vehicle
Is your Corvette, CTS-V, or Trailblazer running rough, stalling unexpectedly, or flashing a persistent check engine light? These are classic signs of a failing Engine Control Module (ECM), the electronic brain of your vehicle. In my 20+ years of diagnosing these complex systems, I’ve seen firsthand how a faulty ECM can cause a cascade of frustrating, hard-to-trace issues. This isn’t just a part; it’s the central command for your engine’s fuel delivery, ignition timing, and emissions systems. When it fails, your vehicle’s performance, fuel economy, and reliability suffer dramatically.
We offer a straightforward, professional solution. This genuine GM Engine Control Module, part number 12678512, is the definitive fix for a wide range of GM cars, trucks, and SUVs. The best part? We handle the most critical step for you. Before this module ships, our technicians will program it with the very latest GM-certified software, specifically matched to your vehicle using your VIN. This eliminates the need for an expensive trip to the dealership and ensures a seamless installation process, whether you’re a seasoned mechanic or a determined DIYer.
A Technician’s Notebook: The Intermittent ZR1 Gremlin
I once had a 2009 Corvette ZR1 in the bay that was a real head-scratcher. The owner reported random misfires and occasional ‘Reduced Engine Power’ warnings, but they’d disappear before he could get to a shop. We checked everything—plugs, coils, fuel pressure—and it all looked perfect. After two days of diagnostics, we finally caught the ECM failing on a data log; the injector driver for cylinder 3 was dropping out intermittently under heat. Swapping in a pre-programmed 2009 Corvette Engine Module like this one solved the problem instantly. It’s a reminder that even on high-performance machines, the core electronics are key to reliability.
Common Signs of a Failing ECM
- ✔ Check Engine Light (CEL) is on with codes like P0601, P0606, or U0100.
- ✔ Engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ Rough idling, stalling, or hesitation during acceleration.
- ✔ Communication errors with diagnostic scan tools.
- ✔ Automatic transmission shifting erratically or harshly.
- ✔ Loss of power or vehicle entering ‘limp mode’.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electronic work.
- ✔ Locate the ECM: On a 2009 Corvette, the ECM is located in the right-front of the engine compartment. On other models, it may be on the firewall or near the airbox. Consult a service manual for your specific vehicle if unsure.
- ✔ Disconnect Connectors: Carefully release the locking tabs on the wiring harness connectors and pull them straight out from the module. Never force them.
- ✔ Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the hardware, as you may need to reuse it.
- ✔ Install the New Module: Mount your new, pre-programmed ECM in place and securely fasten it.
- ✔ Reconnect and Secure: Plug the wiring harnesses back into the new module until they click, and ensure the locking tabs are engaged. Reconnect the negative battery terminal.
- ✔ Perform Security Relearn: You may need to perform a simple security relearn procedure. Typically, this involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine.
Verified Vehicle Compatibility
This module is a direct replacement for a wide array of GM vehicles. Please verify your model and engine below. This part is interchangeable with service numbers: 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464.
- Buick Lucerne: 2009-2011 (4.6L)
- Cadillac CTS: 2009 (6.2L)
- Cadillac DTS: 2009-2011
- Cadillac SRX: 2009 (4.6L)
- Cadillac STS: 2009 (4.4L, 4.6L), 2010 (4.6L)
- Cadillac XLR: 2009
- Chevrolet Colorado: 2009-2012 (2.9L, 3.7L)
- Chevrolet Corvette: 2009 (ZR1)
- Chevrolet Trailblazer: 2009 (6.0L)
- GMC Canyon: 2009-2012 (2.9L, 3.7L)
- GMC Envoy: 2009 (5.3L)
- Hummer H3: 2009-2010 (3.7L)
- Saab 9-7x: 2009
Frequently Asked Questions
Do I need to do any programming myself?
No. We program the module to your specific vehicle using the VIN you provide at checkout. It arrives ready for installation.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to load the exact factory software and calibrations for your car’s specific options, engine, and transmission. This ensures perfect compatibility and performance.
Is this a simple plug-and-play installation?
Yes, for the most part. After physically installing the module, you will need to perform a security relearn procedure, which typically takes about 30 minutes and does not require any special tools. We include instructions for this simple process.
Will this fix my specific problem?
This module will correct issues directly caused by a failing ECM. It’s crucial to properly diagnose your vehicle first. If you have codes like P0601 (Internal Memory Fault) or other ECM-specific errors, this is very likely the solution.
What if I have an aftermarket performance device?
This ECM is flashed with standard GM software. Any aftermarket performance modifications that alter engine software will be overwritten. This module restores the vehicle to its factory operational state.
Are the interchangeable part numbers truly the same?
Yes. GM often updates part numbers over the years. The numbers listed (like 12636659, 12625453, etc.) are all superseded by or are equivalent to 12678512 and will function identically once programmed for your vehicle.