Restore Your Vehicle’s Brainpower and Drive with Confidence
Is your Chevrolet, Buick, or GMC acting up? Stalling at intersections, suffering from poor fuel mileage, or flashing a persistent Check Engine Light? Before you brace for a costly trip to the dealership, the problem might be simpler and more affordable to fix than you think. Often, the culprit is a failing Engine Control Module (ECM), the central computer that manages everything from fuel injection to transmission shifting. This isn’t just a part; it’s the core of your vehicle’s performance and reliability. We offer a dependable, direct-fit solution with this 2012-2016 Sonic Engine Control Module, which also fits a massive range of other GM vehicles.
From the Diagnostic Bay: The Case of the Confusing Cruze
A customer brought in a 2014 Chevy Cruze with the 1.4L engine. It had an intermittent no-start condition and would occasionally stall while driving. They had already replaced the battery and spark plugs with no luck. The scanner pulled a P0606 (ECM/PCM Processor Fault) and a U0100 (Lost Communication With ECM/PCM). In my 20+ years in the bay, I’ve learned that communication codes paired with processor faults almost always point directly to the ECM itself. Internal circuit board failure, often from heat cycles and vibration, is a common weak point. We installed one of our VIN-programmed modules, performed the security relearn, and the car fired up instantly and ran perfectly. This simple swap saved the customer hundreds in dealership diagnostic fees and programming costs.
Is Your GM Vehicle Showing These Signs of ECM Failure?
A failing engine computer can cause a wide array of confusing symptoms. If you’re experiencing any of the following, this module is the likely solution.
- ✔ Check Engine Light is on with codes like P0601, P0606, or other communication errors (U-codes).
- ✔ The engine cranks but refuses to start.
- ✔ Unexplained stalling or rough idling, especially when warm.
- ✔ Noticeable decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Misfires or hesitation during acceleration.
- ✔ Other warning lights (like traction control) illuminate without a clear cause.
A Straightforward Guide to Installation
Replacing the ECM is a job most DIYers can handle in their own driveway. Our pre-programmed module eliminates the most difficult step—the software flashing. Just follow these general steps (always consult a vehicle-specific repair manual for precise locations and torque specs).
- Safety First: Disconnect the negative terminal from your vehicle’s battery and wait a few minutes for the systems to discharge.
- Locate the ECM: On most supported models like the Sonic or Cruze, the ECM is found in the engine bay, often near the battery or firewall. For trucks and vans, it’s typically on the driver’s side front of the engine compartment.
- Disconnect Connectors: Carefully unclip the wiring harness connectors. They have locking tabs, so be gentle and don’t force them. Note their orientation.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed ECM into place.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module. Reconnect the negative battery terminal.
- Perform Security Relearn: You will need to perform a simple key-cycle security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating two more times. This allows the new ECM to sync with your vehicle’s anti-theft system.
Verified Vehicle Compatibility
This ECM, part number 12668866, is a direct replacement for a wide variety of GM cars, trucks, and vans. It interchanges with part numbers 12668994, 12643636, 12663405, and more. Please match your part number or verify fitment with the list below. After purchase, simply provide your VIN, and we will flash the module with the latest GM software for your specific vehicle.
- Buick Encore: 2013-2016 (1.4L)
- Buick ELR: 2014-2016
- Chevrolet Cruze: 2012-2016 (Gasoline, including 1.4L & Limited)
- Chevrolet Silverado 2500/3500: 2012-2016 (6.0L)
- Chevrolet Sonic: 2012-2016
- Chevrolet Spark: 2014-2015 (Gasoline)
- 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 & Denali: 2012-2016 (6.0L)
Frequently Asked Questions
Do I need to do any programming or flashing myself?
No. We handle all the programming for you before we ship the part. Just provide your vehicle’s VIN at checkout, and the module will arrive ready for installation with the latest GM software updates.
What is the ‘security relearn’ and is it difficult?
The security relearn is a simple procedure that syncs the new ECM to your car’s anti-theft system. It typically involves a series of key cycles and takes about 30 minutes. We include instructions, and no special tools are required.
How do I find my original part number?
The part number is printed on a sticker on the case of your current ECM. You can compare it to the list of compatible numbers (12668866, 12643636, etc.) in our listing to confirm a match.
Will this fix my transmission shifting problems?
In many cases, yes. The ECM works directly with the Transmission Control Module (TCM). If the ECM is failing, it can send bad data, causing poor shifting. Replacing a faulty ECM often resolves these related issues.
Is this a reliable, long-term fix?
Absolutely. We provide high-quality, tested modules loaded with factory-correct software. This is designed to restore your vehicle’s original performance and reliability, solving the root cause of many electronic issues.