Restore Your Vehicle’s Performance and Reliability
Is your Cadillac, Chevy, or GMC running rough, stalling, or displaying a persistent check engine light? A failing Engine Control Module (ECM) can be the source of countless frustrating and difficult-to-diagnose issues, leaving you stranded and facing expensive dealership repairs. This genuine GM engine computer is your direct-fit, hassle-free solution. We eliminate the biggest challenge of ECM replacement: the programming. By ordering this Programmed 12636659 ECM, you receive a unit that is professionally flashed with the latest GM software updates, tailored specifically to your vehicle’s unique Vehicle Identification Number (VIN). It’s the most reliable way to get your vehicle back on the road, running exactly as the manufacturer intended.
Common Symptoms & Your Direct Solution
If you’re experiencing any of the following, a faulty ECM is a likely culprit:
- Check Engine Light (CEL) with communication-related codes (e.g., U0100) or processor fault codes (e.g., P0601, P0606).
- Engine stalling, sputtering, or misfiring.
- Complete no-start condition where the engine cranks but won’t fire.
- Noticeable decrease in fuel economy.
- Harsh or erratic transmission shifting.
- Failure to communicate with diagnostic scan tools.
This pre-programmed engine computer is the definitive fix for these problems. It restores the critical connection between your vehicle’s sensors and systems, ensuring precise fuel delivery, ignition timing, and transmission control for a smooth, powerful, and efficient ride.
Features & Benefits
- โ Plug & Play Installation: Arrives pre-programmed to your specific VIN. No additional, expensive dealership flashing is required.
- โ Latest GM Software: We flash each module with the most current updates from General Motors, ensuring optimal performance and longevity.
- โ Guaranteed Compatibility: By matching the programming to your VIN, we ensure perfect communication with your vehicle’s other electronic modules.
- โ Cost-Effective Solution: Get the quality of a dealer-level repair without the exorbitant cost and inconvenience.
- โ Wide-Ranging Fitment: This module is a direct replacement for numerous GM vehicles, including models from Cadillac, Chevrolet, GMC, Hummer, and Saab. See the full fitment list for details.
- โ One-Year Protection: This unit is backed by our one-year replacement warranty, giving you confidence in your repair.
Expert Insight: The Critical Role of VIN Programming
Many people assume you can just swap an ECM from one vehicle to another. This is a critical mistake. Modern vehicles use a sophisticated anti-theft system (like GM’s VATS or Passlock) and have dozens of specific calibrations for the engine, transmission, and even tire size. A Programmed 12636659 ECM isn’t just a convenienceโit’s a necessity. Flashing the module to your VIN ensures the anti-theft system recognizes the new computer, allowing the engine to start. It also loads the precise software ‘map’ your vehicle needs to operate efficiently and safely. Skipping this step will result in a no-start condition at best, and potential damage to other modules at worst.
Frequently Asked Questions
Do I need to do any programming myself?
No. This ECM is a complete plug-and-play solution. We handle all the programming before it ships. You simply need to install it. In some cases, a simple security or crank position sensor relearn procedure may be required, which can be done without special tools.
How do I provide my VIN?
Please enter your 17-digit VIN in the designated field during checkout. You can also reply to your order confirmation email with the VIN. We cannot ship your part until we receive this information.
Is this the correct ECM for my vehicle?
This module is interchangeable with a wide range of service numbers, including 12639300, 12628993, and 12625453. Please review the detailed fitment list on this page. If your original module’s service number is listed, this is the correct part for you.
What if my vehicle has modifications?
Our programming service is designed for stock, unmodified vehicles. We load the official GM calibration that corresponds to your VIN. This service is not intended for vehicles with significant engine or powertrain alterations.
Will this fix my ‘No Communication’ issue?
A ‘No Comms’ situation with a scan tool is a classic symptom of a failed ECM. While this part is often the solution, it’s crucial to first verify that the module is receiving proper power and ground and that the vehicle’s data bus wiring is intact before ordering.