Restore Peak Performance to Your GM Vehicle
Is your Chevrolet Volt, Cruze, or Silverado plagued by a persistent Check Engine Light, erratic stalling, or a frustrating no-start condition? As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Engine Control Module (ECM) can disrupt your vehicle’s entire operation. The ECM is the brain of your engine, and when it falters, it can cause a cascade of confusing and costly problems. This isn’t just an inconvenience; it affects your vehicle’s reliability, fuel efficiency, and safety. This replacement Engine Control Module, part number 12668991, is the definitive solution to get your car or truck running smoothly again.
Case Study: A Tricky Diagnosis
I remember a 2014 Chevy Volt that came into my shop with an intermittent no-start issue that two other shops couldn’t solve. The owner was frustrated, having already replaced the battery and starter. The vehicle would run fine for days, then suddenly refuse to start. No codes were stored initially. After careful testing of the communication network, I noticed a slight voltage drop on the ECM’s power feed during cranking, but only when the fault occurred. It turned out the ECM’s internal voltage regulator was failing under load. We installed one of these pre-programmed modules, and the Volt has been starting reliably ever since. It’s often these subtle internal failures that make a quality, tested part essential.
The Plug-and-Play Advantage: Programmed for Your VIN
The biggest hurdle in replacing a modern ECM is the programming. Dealerships charge a premium for this service, and it requires specialized tools. We eliminate that step entirely. When you purchase this module, simply provide us with your vehicle’s 17-digit VIN. Our certified technicians will flash the unit with the latest, most stable software updates directly from GM. This ensures your new 2011-2015 Volt Engine Control Module—or the correct calibration for your specific GM model—arrives at your door ready for installation. No extra trips to the dealer, no expensive scan tools needed. It’s a direct, effective fix.
Common Signs of a Failing ECM
If you’re experiencing any of the following, a faulty engine computer could be the culprit. A failing ECM can often trigger diagnostic trouble codes (DTCs) like P0601, P0606, or U0100 (Loss of Communication).
- ✔ Check Engine Light is on or flashing
- ✔ Engine stalling or misfiring for no apparent reason
- ✔ Vehicle won’t start, but the battery and starter are good
- ✔ Noticeable drop in fuel economy
- ✔ Poor or hesitant acceleration
- ✔ Automatic transmission shifting erratically
- ✔ Failure to pass an emissions inspection
A Straightforward Guide to Installation
Replacing the ECM is a job most DIYers with basic tools can handle. Follow these steps for a successful installation:
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental reconnection.
- Locate the ECM: On most listed vehicles, the ECM is found in the engine bay. For the Volt and ELR, it’s typically in the LH rear of the engine compartment. For Silverado/Sierra trucks, it’s on the LH front. Consult a repair manual for your specific model if you’re unsure.
- Disconnect Connectors: Carefully release the locking tabs on the electrical 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 will reuse it.
- Install the New Module: Mount your new, pre-programmed ECM onto the bracket and secure it with the original bolts.
- Reconnect Everything: Firmly plug the electrical connectors back into the new module until they click into place. Reconnect the negative battery terminal.
- Perform Relearn Procedure: While the module is plug-and-play, some vehicles may require a security or crankshaft position sensor relearn procedure. This can often be done without special tools (e.g., the ‘key on for 10 minutes, off for 10 seconds’ cycle, repeated three times). Check the specific procedure for your vehicle.
Verified Vehicle Compatibility
This module is a direct replacement for part number 12668991 and is interchangeable with part numbers 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200. It is guaranteed to fit a wide range of GM vehicles, including:
- ✔ Chevrolet Volt: 2011-2015
- ✔ Cadillac ELR: 2014-2016
- ✔ Chevrolet Cruze: 2012-2016 (1.4L & specific IDs)
- ✔ Chevrolet Sonic: 2012-2016 (1.4L & specific IDs)
- ✔ Chevrolet Trax: 2013-2016
- ✔ Buick Encore: 2013-2016 (1.4L)
- ✔ Chevrolet Spark: 2014-2015 (Gasoline)
- ✔ Chevy/GMC Trucks (Silverado, Sierra 2500/3500): 2012-2016 (6.0L)
- ✔ Chevy/GMC Vans (Express, Savana 2500/3500): 2016 (4.8L, 6.0L)
- ✔ Chevrolet Suburban 3500: 2016
How does the VIN programming work?
After you complete your purchase, you will need to send us your vehicle’s 17-digit VIN. We use this number to load the exact, correct GM-certified software for your car’s specific options and configuration. This makes the module ready to install right out of the box.
Is this a simple plug-and-play installation?
Yes, for the most part. Because we program it to your VIN, it eliminates the most difficult step. In some cases, a simple ‘security relearn’ or ‘crankshaft position relearn’ procedure may be required after installation, which typically does not require special tools.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of your original ECM (like with code P0601), then yes, this part is the correct fix. However, you should always ensure other potential issues (sensors, wiring) have been properly diagnosed first.
Do I need to send my old ECM back?
No core charge or return is required for this part. You can keep or recycle your old module.
What if I have a different part number on my old module?
This module replaces several common GM part numbers, including 12668866, 12643636, and others listed above. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.