Restore Peak Performance to Your GM Truck or Van
Is your 2012-2016 GMC Sierra 2500, Silverado 2500, or another compatible GM vehicle suffering from frustrating engine problems? A faulty Engine Control Module (ECM) is often the culprit behind issues like a persistent Check Engine Light, poor fuel economy, stalling, or even a no-start condition. This component is the brain of your vehicle’s engine, and when it fails, it can cause a cascade of problems. This replacement ECM, part number 12668991, is the definitive solution to get your truck back to running smoothly and reliably.
We take the guesswork and hassle out of the replacement process. Unlike a generic module from a local parts store, this ECM is professionally programmed specifically for your vehicle using your VIN. We install the latest, most stable GM-certified software updates available, ensuring optimal performance, fuel efficiency, and emissions control. This means no expensive trips to the dealership for programming—it arrives at your door ready for installation.
Is Your Vehicle Showing Signs of a Failing ECM?
A failing engine computer can manifest in various ways, often mimicking other sensor or component failures. If you’re experiencing any of the following symptoms, a faulty ECM is a likely cause. This 2012-2016 Sierra 2500 ECM is the direct fix for these common issues.
- ✔ Persistent Check Engine Light (CEL) with codes like P0601, P0606, or other internal processor faults.
- ✔ Unexplained drops in fuel economy.
- ✔ Engine stalling, stumbling, or hesitating during acceleration.
- ✔ Rough idling or engine misfires.
- ✔ Difficulty starting the engine or a complete no-start condition.
- ✔ Erratic automatic transmission shifting behavior.
- ✔ Loss of communication with diagnostic scan tools.
From the Diagnostic Bay
We had a 2014 Silverado 2500 with the 6.0L V8 come into the shop with a complaint of intermittent stalling and a flashing Check Engine Light. The owner had already replaced the throttle body and a couple of oxygen sensors based on some generic advice, but the problem persisted. Our initial scan pulled a P0606 code (ECM Processor Fault). Instead of continuing to chase phantom sensor issues, we identified the root cause: the ECM itself was failing internally. We installed a VIN-programmed module just like this one, performed the quick security relearn, and the truck ran perfectly. It’s a classic case of how diagnosing the core problem saves time, money, and a lot of headaches.
The Importance of a VIN-Programmed 2012-2016 Sierra 2500 ECM
Modern vehicles are complex systems. The ECM needs to know everything about your truck’s specific configuration—from the engine and transmission type to the tire size and anti-theft system. Our VIN programming service ensures that the module you receive is a perfect digital match for your vehicle. This critical step guarantees:
- Seamless Integration: The ECM will communicate correctly with all other modules in your vehicle, such as the Transmission Control Module (TCM) and Body Control Module (BCM).
- Correct Engine Operation: Fuel maps, ignition timing, and emissions parameters are set to factory specifications for your exact build.
- Plug-and-Play Installation: Eliminates the need for specialized, expensive scan tools or a trip to the dealer for software flashing.
This module is a direct replacement for a wide range of original equipment part numbers, including 12668866, 12668994, 12643636, 12663405, and more, ensuring broad compatibility across the GM lineup. Please see the detailed fitment list to confirm this part is correct for your specific make, model, and year.
Frequently Asked Questions
Do I need to get this ECM programmed by a dealer?
No. We handle all the programming for you before shipment. Simply provide us with your vehicle’s VIN during or after checkout, and the module will arrive ready to be installed.
Where is the ECM located on my 2012-2016 Sierra or Silverado?
On most 2500/3500 series trucks with the 6.0L engine, the ECM is located in the front of the engine compartment on the driver’s side, near the battery and air filter box.
What is a security relearn procedure?
After installation, you may need to perform a simple security relearn to sync the new ECM with your vehicle’s anti-theft system and keys. This procedure typically takes 10-30 minutes and can be done without any special tools. We can provide instructions upon request.
How do I provide my VIN?
You can add your 17-digit VIN to the notes section during checkout. If you forget, don’t worry—we will contact you via email to request it before we program and ship your part.
Will this fix my P0606 error code?
Yes, the diagnostic trouble code P0606 (Control Module Processor Performance) almost always indicates an internal failure of the ECM. Replacing the module with this pre-programmed unit is the correct and definitive repair for this code.