Restore Peak Performance to Your GM Vehicle
Is your Chevrolet Cruze, Sonic, or other GM vehicle running rough, stalling unexpectedly, or showing a persistent Check Engine Light? As a technician with over two decades of experience under the hood, I’ve seen these symptoms countless times. Often, the root cause isn’t a simple sensor but the very brain of your engine: the Engine Control Module (ECM). A failing ECM can cause a cascade of frustrating, hard-to-diagnose issues, from poor fuel economy to a complete no-start condition. This isn’t just an inconvenience; it’s a reliability problem that can leave you stranded.
This replacement ECM, part number 12668991, is the definitive solution. We take the biggest headache out of the repair process. Before we ship it, we program the module with the latest GM-certified software, specifically matched to your vehicle using your VIN. This means you get a component that is ready for installation right out of the box, restoring the precise fuel delivery, ignition timing, and emissions control your engine was designed for. You’re not just buying a part; you’re getting a reliable, pre-configured fix that bypasses the need for expensive dealership programming.
A Technician’s Notebook: The Cruze That Wouldn’t Communicate
I had a 2014 Chevy Cruze come into my bay that was a real head-scratcher. The owner complained of intermittent stalling at stoplights and a check engine light that came and went. My scan tool pulled a U0100 (Lost Communication With ECM/PCM) code, but all the wiring and connectors looked perfect. Power and ground tests to the module were solid. After chasing my tail for an hour checking the CAN bus network, I decided to trust my gut. On these Ecotec platforms, I’ve seen the internal processors on the ECM begin to fail, causing them to intermittently drop off the network. We installed one of these pre-programmed modules, performed the 10-minute security relearn, and the car ran perfectly. The U-code never returned. It’s a classic case where the problem lies within the component itself, not the surrounding systems.
Common Signs of a Failing ECM
- ✔ Check Engine Light is on with codes like P0601, P0606, or U0100.
- ✔ Your vehicle fails to start or starts and then immediately stalls.
- ✔ Noticeable decrease in fuel efficiency.
- ✔ Engine hesitates, misfires, or runs rough.
- ✔ Automatic transmission shifts erratically or harshly.
- ✔ Loss of communication with your scan tool.
Your Straightforward ECM Installation Guide
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- ✔ Locate the ECM: On most supported vehicles like the Cruze or Sonic, the ECM is typically found in the engine bay, often near the battery or firewall. It’s a silver metal box with several large electrical connectors.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. There are usually locking tabs that need to be released. Once disconnected, unbolt the module from its mounting bracket.
- ✔ Install the New Module: Bolt your new, pre-programmed ECM into place. Reconnect the electrical connectors firmly until they click, ensuring the locking tabs are engaged.
- ✔ Reconnect Power: Re-attach the negative battery terminal and tighten it securely.
- ✔ Perform Security Relearn: This is a critical final step. For most of these GM vehicles, it’s a simple key-on procedure. Turn the key to the ‘ON’ position (without starting the engine) for 10-12 minutes. The ‘Security’ light should turn off. Turn the key off for 10 seconds, then the vehicle should start and run normally.
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 models, including:
- ✔ 2012-2016 Chevrolet Cruze (1.4L & Gasoline Models)
- ✔ 2012-2016 Chevrolet Sonic (1.4L & others)
- ✔ 2013-2016 Buick Encore (1.4L)
- ✔ 2013-2016 Chevrolet Trax
- ✔ 2011-2015 Chevrolet Volt
- ✔ 2014-2016 Cadillac ELR
- ✔ 2014-2015 Chevrolet Spark (Gasoline)
- ✔ 2012-2016 Silverado & Sierra 2500/3500 (6.0L)
- ✔ 2016 Express & Savana Vans (4.8L & 6.0L)
- ✔ 2016 Suburban 3500
Important: Please provide your Vehicle Identification Number (VIN) during checkout. This is mandatory for us to program the module correctly for your specific vehicle before shipping.
Frequently Asked Questions
Do I need to do anything after I install it?
Yes. After installation, you must perform a simple security relearn procedure, which typically involves leaving the key in the ‘ON’ position for about 10-12 minutes. This syncs the new ECM to your vehicle’s anti-theft system. No special tools are required.
Why do you need my VIN?
Your VIN is essential. It allows us to load the exact, correct GM software for your vehicle’s specific engine, transmission, and options. This ensures perfect compatibility and performance, saving you a trip to the dealer for programming.
Is this part difficult to install for a DIYer?
Not at all. The physical replacement is very straightforward, usually involving just a few bolts and electrical connectors. Our pre-programming service handles the most complex part of the job, making this an excellent project for a confident DIY enthusiast.
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) or related communication errors (U-codes), this part is the correct fix. However, you should always diagnose other potential causes like sensors or wiring first.
What if my original part number is not 12668991?
This module is a direct replacement for several part numbers, including 12668866, 12668994, 12643636, and others listed in our description. As long as your vehicle is on the compatibility list, this module will work perfectly once programmed to your VIN.