Restore Peak Performance to Your Vehicle with a VIN-Programmed Engine Computer
Is your Cadillac ELR, Chevy Cruze, or Silverado experiencing frustrating issues like stalling, a persistent check engine light, or a complete no-start condition? The Engine Control Module (ECM), the vehicle’s central computer, is often the culprit. When it fails, it can cause a cascade of problems that are difficult to diagnose. This isn’t just an inconvenience; it’s a critical failure that compromises your vehicle’s reliability and performance. This replacement ECM, part number 12643636, is the definitive solution to get you back on the road with confidence.
As a technician with over two decades of experience, I’ve seen firsthand how a failing ECM can mimic a dozen other problems. Drivers spend hundreds on sensors and parts they don’t need, only to find the root issue was the computer all along. That’s why we offer this module pre-programmed with the latest GM software, specifically matched to your vehicle’s VIN. This eliminates the expensive and time-consuming trip to the dealership for programming, saving you both money and hassle. You’re not just buying a part; you’re buying a complete, ready-to-install solution for your 2014-2016 ELR Engine Control Module and many other compatible GM vehicles.
A Technician’s Notebook: The Intermittent Stall That Wasn’t a Fuel Pump
A customer brought in their 2015 Chevy Cruze with a 1.4L engine, a vehicle that shares this exact ECM with the ELR. The complaint was maddening: the car would run perfectly for days, then suddenly stall at a stoplight and refuse to restart for 10-15 minutes. No consistent codes were stored, just a history of random communication errors. They had already replaced the fuel pump on another shop’s advice, with no change. My diagnostic process led me to monitor the ECM’s internal data. I noticed the 5-volt reference signal, which powers many critical sensors, would intermittently drop out right before a stall. This pointed directly to an internal failure within the ECM. We installed one of our VIN-programmed modules, performed the quick security relearn, and the problem was solved permanently. The customer avoided another costly misdiagnosis and got their reliable daily driver back.
Is Your Vehicle Showing These Common ECM Failure Signs?
- ✔ Check Engine Light is on with communication or internal processor fault codes (e.g., P0601, P0606, U0100).
- ✔ The engine cranks but will not start.
- ✔ Severe performance issues, such as poor acceleration, rough idling, or engine stumbling.
- ✔ A noticeable drop in fuel economy.
- ✔ Intermittent stalling for no apparent reason.
- ✔ Automatic transmission shifting erratically or harshly.
- ✔ The cooling fans run constantly, even when the engine is cold.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- ✔ Locate the ECM: On the 2014-2016 Cadillac ELR, the ECM is found in the left-hand (driver’s side) rear of the engine compartment. For trucks like the Silverado, it’s typically on the LH front of the engine compartment. Consult a service manual if you’re unsure.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. There are typically release tabs that need to be pressed or pulled. Once disconnected, unbolt the old module from its mounting bracket.
- ✔ Install the New Module: Bolt the new, programmed ECM into place. Reconnect the electrical connectors, ensuring they click securely into position.
- ✔ Reconnect Battery: Reattach the negative battery terminal and tighten it securely.
- ✔ Perform Security Relearn: Most GM vehicles require a security relearn procedure to allow the new ECM to communicate with the vehicle’s anti-theft system. This is a simple process that typically takes 10-30 minutes and does not require special tools. Instructions are readily available online for your specific model.
Verified Vehicle Compatibility
This module is a direct replacement for part number 12643636 and other interchangeable numbers like 12668866 and 12668994. It is guaranteed to fit a wide range of GM vehicles. Please verify your part number or contact us with your VIN to ensure an exact match. Key compatible models include:
- ✔ Cadillac ELR: 2014-2016
- ✔ Chevrolet Cruze: 2012-2016 (1.4L & Gasoline models)
- ✔ Chevrolet Sonic: 2012-2016
- ✔ Chevrolet Volt: 2011-2015
- ✔ Chevrolet Trax: 2013-2016
- ✔ Buick Encore: 2013-2016 (1.4L)
- ✔ Chevrolet Silverado 2500/3500: 2012-2016 (6.0L)
- ✔ GMC Sierra 2500/3500 & Denali: 2012-2016 (6.0L)
- ✔ Chevy Express / GMC Savana 2500/3500 Vans: 2016 (4.8L & 6.0L)
- ✔ And more… (see full list in product data)
Frequently Asked Questions
Frequently Asked Questions
Do I need to do anything after I install this ECM?
Yes. While we handle the main programming, you will need to perform a simple vehicle security relearn procedure. This allows the new ECM to sync with your car’s anti-theft system and keys. It’s a straightforward process that usually takes about 30 minutes with no special tools required.
How do I provide my VIN for programming?
After you complete your purchase, you will need to send us your 17-digit Vehicle Identification Number (VIN). We cannot ship your module until we receive this information, as it is essential for programming the correct software for your specific vehicle.
Is this a new or used part?
This is a high-quality, inspected, and tested recycled OEM part. Each module is verified to be fully functional before being programmed with the latest GM software updates for your vehicle.
What if the part number on my old module is different?
This module (12643636) supersedes and replaces several other GM part numbers, including 12668866, 12668994, and 12663405. As long as your vehicle is on our compatibility list, this module will function correctly once programmed to your VIN.
Will this fix my car’s specific problem?
This module will correct issues directly caused by a faulty ECM. While the symptoms we’ve listed are common indicators of ECM failure, we always recommend a proper diagnosis by a qualified mechanic to confirm the ECM is the root cause before ordering.