Restore Peak Performance to Your GM Truck or Van
As a technician with over two decades of experience under the hood, I’ve seen firsthand the frustration a failing Engine Control Module (ECM) can cause. Your 2012-2016 Sierra 2500 is a workhorse, but when its electronic brain starts to falter, you’re left with a truck that’s unreliable and inefficient. Symptoms like a persistent check engine light, rough idling, stalling, or a complete no-start situation can bring your work to a halt. This isn’t just an inconvenience; it’s a critical failure that needs a reliable solution.
This isn’t just a part; it’s a complete, ready-to-install fix. We take a genuine GM ECM, part number 12670335, and professionally flash it with the very latest GM-certified software specific to your truck’s Vehicle Identification Number (VIN). This crucial step ensures that all fuel trim, transmission shift points, and emissions parameters are perfectly calibrated for your exact vehicle, restoring the performance and reliability you depend on. By ordering this 2012-2016 Sierra 2500 ECM, you’re bypassing the expensive dealership programming fees and lengthy wait times.
Case Study: A Tricky Diagnosis
A customer brought in his ’14 Sierra 2500 with the 6.0L V8, complaining of intermittent stalling at stoplights and a weird hesitation under light acceleration. No consistent check engine light, just a history code for U0100 (Lost Communication with ECM/PCM) and a P0601 (Internal Control Module Memory Check Sum Error). We checked all the wiring and grounds—they were perfect. The issue was the ECM itself, suffering from internal heat-related stress. Swapping in a pre-programmed module like this one had him back on the road in under an hour, with the issue completely resolved. These symptoms can be elusive, but often, the module itself is the root cause.
Is Your Truck or Van Showing These Red Flags?
- ✔ Persistent Check Engine Light (CEL)
- ✔ Engine stalling or shutting off while driving
- ✔ Rough or erratic idle
- ✔ No-start or hard-start conditions
- ✔ Noticeable decrease in fuel economy
- ✔ Transmission shifting issues or harsh shifts
- ✔ Common Diagnostic Trouble Codes (DTCs) like P0601, P0606, or U0100
A Straightforward Guide to Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- ✔ Locate the ECM: On most 2012-2016 Sierra/Silverado 2500 models with the 6.0L engine, the ECM is located in the front left (driver’s side) of the engine compartment, often near the battery or air filter box.
- ✔ Disconnect Connectors: Carefully unclip and remove the electrical wiring harnesses connected to the old ECM. Take your time to avoid damaging the locking tabs.
- ✔ Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the hardware as you may need to reuse it.
- ✔ Install the New Module: Mount your new, pre-programmed ECM onto the bracket and secure it.
- ✔ Reconnect Everything: Plug the wiring harnesses firmly into the new module until they click into place. Reconnect the negative battery terminal.
- ✔ Perform Security Relearn (If Necessary): In many cases, the vehicle will start right up. However, some GM vehicles require a simple security relearn procedure. This can typically be done by turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times before starting the engine.
With this pre-programmed 2012-2016 Sierra 2500 ECM, you get a direct-fit component that restores your vehicle’s core functions without the need for specialized dealer tools. It’s the smart, efficient way to get your truck running right.
Verified Vehicle Compatibility
This module is a direct replacement for part numbers 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200. It fits a wide range of GM vehicles, including but not limited to:
- ✔ 2012-2016 Sierra 2500/3500 Pickup (6.0L)
- ✔ 2012-2016 Silverado 2500/3500 Pickup (6.0L)
- ✔ 2016 Express/Savana 2500/3500 Van (4.8L, 6.0L)
- ✔ 2016 Suburban 3500
- ✔ 2011-2015 Volt
- ✔ 2012-2016 Sonic (1.4L)
- ✔ 2012-2016 Cruze (Gasoline)
- ✔ 2013-2016 Trax (1.4L)
- ✔ 2013-2016 Encore (1.4L)
- ✔ 2014-2016 ELR
- ✔ 2014-2015 Spark (Gasoline)
Please provide your VIN upon purchase to ensure we flash the correct, most current software for your specific vehicle and options. This is the final step in guaranteeing a perfect match for your 2012-2016 Sierra 2500 ECM or other compatible model.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to access the exact GM factory calibration file for your truck. This includes specifics for the engine, transmission, emissions equipment, and even tire size. Programming the ECM with this data is essential for proper vehicle operation.
Is this a plug-and-play part?
Yes, because we program it to your VIN before shipping, it is designed to be a plug-and-play solution. In some cases, a simple 10-30 minute key-cycle security relearn procedure may be required, which does not need any special tools.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the ECM (common codes P0601, P0606), this replacement module will resolve the issue. It’s crucial to ensure the problem isn’t with a sensor or wiring before ordering.
What’s the difference between an ECM and a PCM?
The terms are often used interchangeably. ECM stands for Engine Control Module, while PCM means Powertrain Control Module. In most modern vehicles like your Sierra, the PCM controls both the engine and the transmission, so it serves as the ECM as well.
Do I need to send my old ECM back?
This listing does not require a core return. You can keep or responsibly dispose of your old module.