Restore Your Vehicle’s Core Performance with a Reliable Engine Control Module
Is your Chevrolet, Buick, or GMC vehicle suffering from frustrating issues like a persistent check engine light, erratic engine behavior, or a no-start condition? The Engine Control Module (ECM), often called the engine’s brain, is the central command unit responsible for managing everything from fuel mixture and ignition timing to emissions and transmission shifting. When it begins to fail, it can cause a cascade of problems that are often difficult to diagnose.
As a technician with over two decades of experience, I’ve seen firsthand how a faulty ECM can mimic other component failures, leading to wasted time and money on incorrect repairs. This is especially true for the versatile GM ECM, part number 12668866. This isn’t just a part in a box; it’s a comprehensive solution. We take the guesswork and high dealership costs out of the equation by professionally programming this module to your vehicle’s specific Vehicle Identification Number (VIN) before it even ships. This ensures it arrives ready for installation, loaded with the latest GM software updates for optimal performance and efficiency.
Case Study: A Tricky Diagnosis
A customer brought in a 2014 Chevy Cruze with an intermittent stalling problem that no one could solve. The car would run fine for days, then suddenly die at a stoplight. There were no consistent trouble codes, just a random U0100 (Lost Communication with ECM/PCM). After checking all the usual suspects—battery, alternator, wiring harnesses—we focused on the ECM itself. Internal processor faults can be sporadic and don’t always set a hard code like a P0606. We swapped in one of our pre-programmed 2011-2015 Volt Engine Module compatible units (this ECM fits many models), and the problem vanished instantly. The customer saved hundreds compared to a dealership diagnosis and programming fee.
Is Your Vehicle Showing These Signs of ECM Failure?
A failing engine computer can manifest in numerous ways. If you’re experiencing any of the following, a faulty ECM could be the culprit. Look out for these common symptoms and diagnostic trouble codes (DTCs):
- ✔ Check Engine Light is illuminated with codes like P0601, P0602, P0606, or U0100.
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained drops in fuel economy.
- ✔ Engine stalling, stuttering, or misfiring.
- ✔ Rough or inconsistent idling.
- ✔ Automatic transmission shifting issues or harshness.
- ✔ Loss of power and poor acceleration.
A Straightforward Guide to Your ECM Installation
Installing your new engine module is a manageable job for a confident DIYer. Following these steps will help ensure a smooth process. Always consult a vehicle-specific repair manual for detailed instructions and torque specs.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the ECM: On most listed vehicles, the ECM is found in the engine compartment. For the 2011-2015 Volt, it’s in the left-hand rear of the engine bay. For Silverado/Sierra trucks, it’s on the left-hand front side.
- Disconnect Connectors: Carefully release the locking tabs on the wiring harness connectors and pull them straight out from the module. Never force them. Inspect the pins for any corrosion or damage.
- 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 in place and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harness connectors back into the new module until they click into place. Reconnect the negative battery terminal.
- Perform Relearn (If Necessary): While this unit is pre-programmed, some vehicles require a brief security or crank-position sensor relearn procedure. This can often be done without special tools—check your vehicle’s service information. Start the vehicle and check for proper operation.
Verified Vehicle Compatibility for Part 12668866
This engine control module is a direct-fit replacement for a wide range of General Motors vehicles. Please verify your vehicle is on this list and provide your VIN upon purchase to ensure correct programming. This module is compatible with part numbers 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200.
- Buick Encore: 2013-2016 (1.4L)
- Cadillac ELR: 2014-2016
- Chevrolet Cruze: 2012-2016 (1.4L & Gasoline Models)
- 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 (Gasoline Model)
- Chevrolet Suburban 3500: 2016
- Chevrolet Trax: 2013-2016
- Chevrolet Volt: 2011-2015 (Gasoline Engine Module)
- GMC Savana 2500/3500 Van: 2016 (4.8L, 6.0L)
- GMC Sierra 2500/3500 Pickup (incl. Denali): 2012-2016 (6.0L)
Why do you need my VIN?
Your VIN (Vehicle Identification Number) is essential for us to program the engine module with the exact software and calibrations specific to your vehicle’s factory options, engine, and transmission. This ensures it works correctly right out of the box.
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 rare cases, a simple security or sensor relearn procedure may be needed, which can typically be done without a scan tool.
Will this fix my check engine light?
If the check engine light is caused by a faulty ECM (e.g., codes P0601-P0606), then this replacement module will resolve the issue. It’s crucial to properly diagnose the problem first, as the light can indicate issues with other sensors or components.
Where is the ECM located on my 2013 Chevy Volt?
For the 2011-2015 Chevrolet Volt, the gasoline engine’s control module is located in the left-hand (driver’s side) rear corner of the engine compartment.
Is this part difficult to install myself?
For someone with basic mechanical skills and tools, replacing an ECM is generally a straightforward process. The most important parts are disconnecting the battery first and being gentle with the wiring connectors. Please see our installation guide above.