2012-2016 Sierra 3500 ECM 12643636 Programmed | VIN Matched

Is Your Sierra 3500 Running Rough or Not Starting?

As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Engine Control Module (ECM) can bring a powerful truck like the 2012-2016 Sierra 3500 to a dead stop. You rely on your truck for tough jobs, and when the brain of the engine falters, it can cause a cascade of frustrating and confusing problems. You might be experiencing issues that have you chasing your tail, replacing sensors and other parts with no success.

A customer’s 2014 Sierra 3500 with the 6.0L engine came into my shop last month with these exact symptoms. It had intermittent stalling, a check engine light that wouldn’t stay off, and a P0606 (ECM Processor Fault) code. After confirming the battery, alternator, and all main power and ground connections to the ECM were solid, we knew the module itself was the point of failure. The internal processor was failing, a common issue I’ve diagnosed on these GM platforms.

Common Symptoms of a Failing GM ECM:

• ✔ Check Engine Light (CEL) with communication-related or internal processor fault codes (e.g., P0601, P0606).
• ✔ Engine stalling, stumbling, or hesitating for no apparent reason.
• ✔ Complete no-start condition where the engine cranks but won’t fire up.
• ✔ Poor fuel economy and a noticeable loss of power.
• ✔ Erratic transmission shifting or other module communication errors.

Why Our 2012-2016 Sierra 3500 ECM is the Smart Choice

Don’t let a faulty computer keep your truck sidelined. This Engine Control Module is the reliable, direct-fit solution you need. The biggest hurdle with replacing an ECM is the programming—typically, you’d have to buy the part, install it, and then have your truck towed to a dealership for an expensive programming session. We eliminate that entire process. We handle the critical programming before we ship the part to you.

Simply provide us with your vehicle’s VIN (Vehicle Identification Number) during checkout, and our technicians will flash the module with the latest, most stable software updates directly from GM. This ensures perfect compatibility and optimal performance right out of the box. It’s a true plug-and-play solution designed for the DIYer and professional mechanic alike.

Plug-and-Play Installation: No Dealer Visit Required

1. Safety First: Disconnect the negative terminal from your truck’s battery to prevent any electrical shorts.
2. Locate the ECM: On the 2012-2016 Sierra 3500 with the 6.0L engine, the ECM is typically located in the front left (driver’s side) of the engine compartment.
3. Disconnect and Remove: Carefully unplug the electrical connectors. There are usually locking tabs that need to be released. Once disconnected, unbolt the old module from its mounting bracket.
4. Install the New ECM: Mount your new, pre-programmed ECM in place and securely fasten the bolts. Reconnect the electrical harnesses, ensuring they click firmly into place.
5. Reconnect and Start: Reattach the negative battery terminal. The vehicle may require a security relearn procedure, which typically involves turning the key to the ‘ON’ position for 10-15 minutes. Then, start your engine and enjoy restored performance.

Guaranteed Compatibility

This module is a direct replacement for a wide range of GM vehicles and part numbers. If your original module has one of the following numbers, this part is the correct fit for you:

Replaces Part Numbers: 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, 12692200

Extensive Vehicle Fitment:

While this is the correct part for the 2012-2016 Sierra 3500 ECM with the 6.0L engine, it also fits a broad array of other GM models, including the Silverado 2500/3500, Express/Savana Vans, Cruze, Sonic, Trax, Encore, and more. Please verify the part number or use the fitment chart to confirm compatibility with your specific vehicle and options.