Is Your GM Truck or SUV Experiencing Critical Engine Problems?
If your 2014-2016 GMC Sierra, Chevy Silverado, or other compatible GM vehicle is suffering from a persistent Check Engine Light, erratic performance, stalling, or a no-start condition, a failing Engine Control Module (ECM) is a very likely culprit. The ECM is the central computer of your vehicle’s powertrain, responsible for managing everything from fuel injection and ignition timing to transmission shifting and emissions control. When it fails, it can cause a cascade of frustrating and potentially damaging issues, leaving your vehicle unreliable and unsafe to drive.
From the Diagnostic Bay
We had a 2015 Silverado 1500 come in on a tow truck. The owner had already replaced two throttle bodies and a MAP sensor trying to chase down an intermittent stalling issue and a flurry of communication codes. The truck would run fine for a few days, then suddenly die at a stoplight. After confirming all sensor wiring and power/ground circuits to the ECM were solid, we identified the internal processor of the original ECM was failing under thermal load. Installing a properly programmed Sierra 1500 ECM resolved all the codes and performance issues instantly. It’s a reminder that chasing parts can be expensive; starting with a proper diagnosis of the vehicle’s central computer is often the most direct path to a lasting repair.
Common Symptoms of a Failing ECM
- ✔ Persistent Check Engine Light (CEL) that won’t clear.
- ✔ Diagnostic trouble codes related to module communication (U-codes) or processor faults.
- ✔ Unexplained engine stalling, hesitation, or rough idling.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Intermittent or complete no-start condition where the engine cranks but won’t fire.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Misfire codes on one or multiple cylinders that aren’t resolved by new plugs or coils.
- ✔ Other electronic systems like traction control or ABS acting erratically.
The Direct Solution: A Programmed 2014-2016 Sierra 1500 ECM
Don’t let a faulty computer keep your truck off the road. This genuine GM Engine Control Module, part number 12663391, is the definitive solution. We take the guesswork and high dealership costs out of the equation. Before we ship the part, our technicians will program it using the latest GM software updates specifically for your vehicle’s Vehicle Identification Number (VIN). This ensures that when you receive the module, it’s ready for installation and configured to the exact specifications of your truck’s engine, transmission, and options package.
This process eliminates the need for expensive dealer-only programming tools, saving you hundreds of dollars and significant downtime. The module is a direct-fit replacement, designed to restore the precise performance and reliability you expect from your vehicle.
Wide-Ranging GM Compatibility
While this is a perfect solution for the Sierra 1500 ECM, this module (and its compatible part numbers like 12692067, 12676230, and 12656993) is the factory-specified computer for a wide array of high-performance and luxury GM vehicles from this era. This includes, but is not limited to:
- Chevrolet Silverado 1500
- Cadillac Escalade, ATS, CTS, and XTS
- Chevrolet Corvette and Camaro
- GMC Yukon / Yukon XL
- Chevrolet Suburban / Tahoe
- GMC Canyon / Chevrolet Colorado
Please verify your original part number or consult the detailed fitment list to ensure this is the correct component for your specific application.
Simple Installation Process
Installation is straightforward for a DIY mechanic or any professional technician. After disconnecting the vehicle’s battery, you will locate the existing ECM (typically in the LH front of the engine compartment on trucks and SUVs), carefully disconnect the electrical connectors, unbolt the module, and install the new one in its place. Once the new module is secured and reconnected, and the battery is back online, you will need to perform a simple security relearn procedure, which pairs the new ECM to your vehicle’s anti-theft system. This procedure typically does not require special tools and instructions can be readily found for your specific model.
Frequently Asked Questions
How do I provide my VIN for programming?
After you complete your purchase, you will receive instructions on how to reply with your 17-digit Vehicle Identification Number (VIN). We cannot ship your order until we receive this information, as the programming is essential for the part to function in your vehicle.
Is any additional programming required after installation?
No. The module arrives fully programmed for engine and transmission operation. The only step you may need to perform is a Security Relearn Procedure (also known as a Passlock or Passkey relearn), which syncs the new ECM with your vehicle’s anti-theft system. This can typically be done without any special tools.
Will this fix my vehicle’s problem?
This ECM will correct any issues directly caused by a faulty original engine computer. However, it is crucial that your vehicle has been properly diagnosed. This part will not fix problems related to bad sensors, faulty wiring, or mechanical failures. We recommend a thorough diagnosis by a qualified technician to confirm the ECM is the point of failure.
Is this a new or used part?
This is a high-quality, tested, and guaranteed functional OEM part. Each module is meticulously inspected and programmed with the latest software from GM to ensure optimal performance and longevity.
Where is the ECM located on my 2015 Sierra?
On most 2014-2016 GM trucks and SUVs like the Sierra, Silverado, and Tahoe, the Engine Control Module is located in the engine bay, on the driver’s side, near the front fender and airbox.