Is Your Sierra 3500 Running Rough, Stalling, or Throwing Codes?
As a mechanic with over two decades of experience under the hood, I’ve seen my fair share of work trucks pushed to their limits. A 2014 Sierra 3500 with the 6.0L V8 was towed into my shop last month with a classic case of ECM failure. The owner reported intermittent stalling at traffic lights, a check engine light that wouldn’t stay off, and a transmission that seemed to have a mind of its own. After confirming power and grounds were solid, the scan tool pointed to an internal processor fault in the Engine Control Module. This is the exact, reliable solution we used to get that truck back on the job site the very next day.
This is a genuine GM Engine Control Module (ECM), part number 12668866, which serves as the brain for your truck’s engine and transmission. A failing ECM can cause a cascade of frustrating problems, but the fix is easier than you think. We take the guesswork and dealer expense out of the equation by programming this module specifically for your vehicle’s VIN before it ever leaves our facility.
Why Choose Our Pre-Programmed 2012-2016 Sierra 3500 ECM?
You’re not just buying a part; you’re buying a complete, ready-to-install solution. We handle the complex programming so you can handle the straightforward installation.
- โ VIN-Specific Programming Included: We flash the module with the latest GM-certified software for your exact 2012-2016 Sierra 3500. Just provide your VIN at checkout.
- โ Eliminates Dealer Visits: Save hundreds of dollars and the hassle of towing your truck to a dealership for programming. This module is ready to go right out of the box.
- โ Resolves Common Failure Symptoms: Effectively corrects issues like no-start conditions, poor fuel economy, erratic engine behavior, and communication-related fault codes.
- โ Direct-Fit OEM Replacement: Guaranteed to match the form and function of your original module for a seamless installation.
Expert Pro Tip: Check Your Grounds Before Installation
Before you install your new ECM, take 5 minutes to inspect the main engine-to-chassis ground strap. On these GM trucks, it’s often a braided strap near the firewall on the passenger side. I’ve seen dozens of cases where a corroded or loose ground causes voltage spikes that can damage the new module and mimic the symptoms of a bad ECM. A quick cleaning with a wire brush can save you a massive headache and protect your investment.
Simple Plug-and-Play Installation
Getting your truck back to peak performance is a straightforward process. No advanced mechanical skills are required.
- Safety First: Disconnect the negative terminal from your truck’s battery.
- Locate the ECM: On the 2012-2016 Sierra 3500, the ECM is located in the front of the engine bay on the driver’s side, near the battery and air filter box.
- Disconnect Connectors: Carefully unclip the wiring harness connectors from the old module. Inspect the pins for any corrosion or damage.
- Swap the Modules: Unbolt the old ECM and mount the new one in its place.
- Reconnect Everything: Securely plug the wiring harnesses into your new module and reconnect the negative battery terminal.
- Perform Security Relearn: Your truck may require a simple security relearn procedure. Typically, this involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and then starting the engine. Your vehicle’s manual will have the specific steps.
Guaranteed Fitment for a Wide Range of GM Vehicles
This module is a direct replacement for part numbers 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200. It is compatible with a vast array of GM models, including:
- Buick Encore: 2013-2016 (1.4L)
- Cadillac ELR: 2014-2016
- Chevrolet Cruze: 2012-2016 (1.4L & Limited)
- 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)
- Chevrolet Spark: 2014-2015
- Chevrolet Suburban 3500: 2016
- Chevrolet Trax: 2013-2016
- Chevrolet Volt: 2011-2015
- GMC Savana 2500/3500 Van: 2016 (4.8L, 6.0L)
- GMC Sierra 2500/3500 Pickup (including Denali): 2012-2016 (6.0L)