Restore Your Truck’s Performance and Reliability
Is your 2012-2016 Sierra 3500 Pickup acting up? A faulty Engine Control Module (ECM) is often the hidden culprit behind a host of frustrating issues, from a persistent Check Engine Light to unpredictable stalling or poor engine performance. As the ‘brain’ of your vehicle, the ECM governs critical functions like fuel mixture, ignition timing, and transmission shifting. When it fails, it can make your dependable workhorse feel unreliable. This direct-fit ECM, part number 12663405, is the definitive solution to get your truck running right again.
We take the guesswork and hassle out of the repair. Unlike sourcing a module from a salvage yard, which would require expensive dealership programming, this unit arrives at your door fully programmed to your specific vehicle. We use your truck’s Vehicle Identification Number (VIN) to load the latest, most stable GM factory software. This ensures seamless integration and optimal performance right out of the box, restoring the power and efficiency you depend on. This is the most effective way to address issues stemming from a faulty 2012-2016 Sierra 3500 ECM.
Case Study: A Tricky Diagnosis
A 2014 Silverado 2500 with the 6.0L V8 came into my bay with a bizarre complaint: it would randomly lose power and the gauges would flicker, but it never threw a consistent trouble code. The owner had already replaced the battery and alternator. After hours of chasing wires, I checked for communication with the ECM and found intermittent dropouts. It turned out the main processor on the original ECM was failing under heat load, causing these ghost-like problems. Installing a pre-programmed module like this one resolved all the issues in under an hour. It’s a reminder that a failing ECM doesn’t always set a clear P0601 ‘Internal Memory Failure’ code.
Is Your Sierra Exhibiting These Symptoms?
A failing ECM can manifest in numerous ways. If you’re experiencing any of the following, it’s a strong indicator that your engine computer needs attention:
- âś” Check Engine Light is on with communication-related or internal processor codes (e.g., P0601, P0606, U0100).
- âś” The engine cranks but refuses to start.
- âś” Unexplained drops in fuel economy.
- âś” Rough or erratic idling and stalling.
- âś” Harsh or incorrect automatic transmission shifting.
- âś” Failure to pass state emissions testing.
- âś” Loss of power or sluggish acceleration.
A Straightforward Guide to Installation
Replacing your 2012-2016 Sierra 3500 ECM is a manageable job for a confident DIYer. With our pre-programmed module, you skip the most complicated step. Always consult a vehicle-specific repair manual, but here are the general steps:
- Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
- Locate the ECM: On these trucks, the ECM is typically found in the engine bay on the driver’s side, near the firewall or inner fender.
- Disconnect Wiring: Carefully release the locking tabs and unplug the large electrical connectors from the old module. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New ECM: Mount your new, pre-programmed ECM onto the bracket and securely fasten the bolts.
- Reconnect Wiring: Plug the electrical connectors firmly into the new module. You should hear or feel them click into place.
- Final Step: Reconnect the negative battery terminal. In some cases, a security relearn procedure may be required, which can often be done without special tools (instructions are widely available online or in your manual).
Verified Vehicle Compatibility
This ECM is a direct replacement for multiple part numbers and fits a wide range of GM vehicles. While this listing is focused on the 2012-2016 Sierra 3500 ECM with the 6.0L engine, it is also compatible with the following models and part numbers: 12668866, 12668994, 12643636, 12670335, 22819494, and 12692200.
Fits Models Including:
- Buick Encore (2013-2016, 1.4L)
- Cadillac ELR (2014-2016)
- Chevrolet Cruze (2012-2016, 1.4L & others)
- Chevrolet Express 2500/3500 Van (2016, 4.8L/6.0L)
- Chevrolet Silverado 2500/3500 Pickup (2012-2016, 6.0L)
- Chevrolet Sonic (2012-2016, 1.4L & others)
- Chevrolet Spark (2014-2015)
- Chevrolet Trax (2013-2016)
- Chevrolet Volt (2011-2015)
- GMC Savana 2500/3500 Van (2016, 4.8L/6.0L)
- GMC Sierra 2500/3500 Pickup & Denali (2012-2016, 6.0L)
- Suburban 3500 (2016)
Please ensure your vehicle and options match the list. Providing your VIN at checkout is essential for us to guarantee a perfect match and proper programming.
Frequently Asked Questions
Do I need to do any programming myself?
No. This ECM comes fully programmed to your vehicle’s VIN with the latest GM software updates. It is designed to be a plug-and-play solution, though a simple key relearn or security relearn procedure may be necessary after installation.
Where do I provide my VIN?
After you complete your purchase, you will need to send us your 17-digit VIN. You can typically add it as a note during checkout or send it to us in a message referencing your order number. We cannot ship the part until we receive your VIN.
Will this fix my ‘No Start’ problem?
If the ‘no start’ condition is caused by a faulty ECM, then yes, this part will resolve the issue. Common signs of an ECM-related no-start include the engine cranking normally but not firing, or no communication with the scan tool. However, other parts like a crank sensor or fuel pump can also cause a no-start, so proper diagnosis is key.
Is this a used part?
This is a high-quality, tested, and verified recycled OEM part. Each module is inspected and then programmed with fresh, vehicle-specific software, ensuring it functions like new and provides a reliable, long-term repair.
What if my original part number is not 12663405?
This module is a direct replacement for several interchangeable part numbers, including 12668866, 12668994, 12643636, and others listed in the description. As long as your vehicle is listed in the compatibility chart, this module will work once programmed to your VIN.