Restore Your Truck’s Performance and Reliability
Is your 2014-2016 GMC Sierra 1500 or other compatible GM vehicle suffering from frustrating issues like a persistent check engine light, poor fuel economy, erratic shifting, or a no-start condition? A failing Engine Control Module (ECM) is often the culprit. As the ‘brain’ of your vehicle, the ECM controls everything from fuel mixture and ignition timing to transmission shift points. When it falters, the symptoms can be widespread and confusing. This replacement Engine Control Module, part number 12663391, is the definitive solution to get your truck running like new again.
We take the guesswork and expensive dealership trips out of the equation. Unlike a generic module from a parts store, this ECM arrives at your doorstep pre-programmed with the latest official GM software, specifically flashed to your vehicle’s unique VIN. This ensures perfect communication between all onboard systems and eliminates the need for expensive programming tools. It’s a direct-fit, reliable solution designed for both professional technicians and capable DIYers.
From the Diagnostic Bay: The Intermittent No-Start Mystery
A customer brought in his 2015 Sierra 1500 with a problem that was driving him crazy: intermittent no-start. Sometimes it would fire right up, other times it would just crank. There were no consistent trouble codes, just a few random communication errors (U-codes) that would come and go. After checking all the basics—battery, starter, grounds—I hooked up my scope. I noticed the 5-volt reference signal to a few key sensors would occasionally drop out during cranking. In my 20+ years of experience, this almost always points to an internal failure in the ECM’s power supply board. We installed one of these VIN-programmed modules, performed the security relearn, and the truck has started flawlessly ever since. It’s a classic case where the 2014-2016 Sierra 1500 ECM was slowly failing internally, causing ghost-like problems that are hard to pin down without experience.
Is Your Vehicle Showing These Symptoms?
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (ECM/PCM Processor Fault).
- ✔ Vehicle has a no-start or hard-start condition.
- ✔ A noticeable drop in fuel economy.
- ✔ The engine runs rough, stalls, or misfires.
- ✔ Automatic transmission shifts harshly or at the wrong times.
- ✔ Loss of communication with the module (U-codes).
- ✔ Failure to pass state emissions testing.
Your Straightforward Installation Guide
Installing your new 2014-2016 Sierra 1500 ECM is a manageable job for a DIYer with basic tools. The most critical part is the Security Relearn Procedure, which pairs the new module to your vehicle’s anti-theft system.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow all systems to discharge.
- Locate the ECM: On most Sierra/Silverado models, the ECM is located in the front of the engine compartment on the driver’s side, near the air filter box.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that need to be released. Once disconnected, unbolt the old module from its bracket and remove it.
- Install the New ECM: Bolt the new, pre-programmed ECM into place. Reconnect the wiring harness connectors, ensuring they click securely into place. Reconnect the negative battery terminal.
- Perform Security Relearn (CRITICAL STEP): Do not attempt to start the engine yet. Turn the key to the ‘ON’ position (without starting). Try to start the engine; it will crank but not start, and the security light will be on or flashing. Leave the key in the ‘ON’ position for 10-12 minutes, or until the security light turns off. Turn the key off for 5 seconds. Repeat this cycle two more times for a total of three 10-minute cycles. After the third cycle, the vehicle should start and run normally.
Verified Vehicle Compatibility
This module is a direct replacement for part number 12663391 and is interchangeable with several other part numbers. It fits a wide range of GM vehicles. Please confirm your vehicle is on this list before ordering. After purchasing, you must provide your VIN so we can program the module for you.
- ✔ GMC Sierra 1500 / Denali 1500: 2014, 2015, 2016
- ✔ Chevrolet Silverado 1500: 2014, 2015, 2016
- ✔ GMC Yukon / Yukon XL 1500: 2015, 2016
- ✔ Chevrolet Tahoe / Suburban 1500: 2015, 2016
- ✔ Cadillac Escalade / ESV: 2015, 2016
- ✔ Chevrolet Corvette: 2014-2016
- ✔ Chevrolet Camaro: 2016 (6.2L)
- ✔ Cadillac CTS: 2014-2016 (3.6L & 6.2L)
- ✔ Cadillac ATS: 2014-2016 (3.6L)
- ✔ Cadillac XTS: 2014-2016 (3.6L)
- ✔ GMC Canyon: 2015-2016 (3.6L)
- ✔ Chevrolet Colorado: 2015-2016 (3.6L)
Frequently Asked Questions
Frequently Asked Questions
Do I need to do anything after I buy it?
Yes. After you place your order, you MUST send us your vehicle’s 17-digit VIN. We cannot ship your part until we have this information to program the module correctly.
Is this a simple plug-and-play installation?
It’s very close. The module is pre-programmed, so no special computer tools are needed. However, you must perform the security relearn procedure as outlined in our installation guide. It’s a simple process that takes about 30 minutes using only your ignition key.
Will this fix my specific problem?
This module corrects issues directly caused by a failing ECM, such as internal processor faults (P0601, P0606) and other common symptoms. While it is a very common failure point, you should always ensure your vehicle has been properly diagnosed. This part will not fix problems related to other bad sensors or wiring issues.
What if my original part number is not 12663391?
This module is a direct replacement for several part numbers, including 12692067, 12676230, 12656993, 12662034, and others listed in the fitment data. As long as your vehicle model and year are listed, this programmed module will work correctly.
What is the benefit of getting the latest GM software?
Manufacturers often release software updates to address common issues, improve transmission shifting, and optimize engine performance and efficiency. By programming this module with the latest software for your VIN, you’re getting a solution that’s often better than the one your vehicle originally came with.