Restore Your Vehicle’s Brain and Drivability
Is your Cadillac ELR, Chevy Cruze, or Silverado experiencing baffling issues like intermittent stalling, a persistent check engine light, or a complete no-start condition? These are classic signs of a failing Engine Control Module (ECM), the critical computer that manages your engine’s performance. When the ECM falters, it can feel like your vehicle has lost its mind, leading to frustrating diagnostic dead ends and expensive trips to the dealership. This isn’t just an inconvenience; a faulty ECM can impact fuel economy, emissions, and overall vehicle safety.
We offer a straightforward, reliable solution. This is a direct-fit Engine Control Module, part number 12643636, that arrives at your door pre-programmed to your specific vehicle. Simply provide us with your Vehicle Identification Number (VIN) after your purchase, and our experts will flash the module with the latest, most stable software updates directly from GM. This eliminates the need for expensive programming tools or a costly visit to a dealership service center. You get a component that is ready for installation right out of the box, designed to restore the precise engine management your vehicle had when it left the factory.
A Technician’s Notebook: The Ghost in the Machine
I once had a 2015 Chevy Volt (which uses a similar ECM system to the ELR) come into my shop with a problem that was maddening two other mechanics. The car would randomly refuse to switch from electric to gasoline mode, throwing a generic communication error (U0100) and then operating perfectly fine for days. We checked wiring, sensors, and the high-voltage system—all checked out. On a hunch, I monitored the ECM’s internal temperature data during a long test drive. I noticed that right before the fault, the reported temperature would spike erratically. The ECM’s internal processor was failing under thermal stress, but only intermittently. Replacing the ECM with a properly programmed unit solved the problem instantly. It’s a perfect example of how a failing module can create symptoms that seem completely unrelated to the source.
Is Your Vehicle Showing These Telltale ECM Failure Symptoms?
A failing engine computer can manifest in numerous ways. If you’re experiencing any of the following, a faulty ECM could be the culprit. This is especially true if the issues are intermittent and you’re seeing communication-related Diagnostic Trouble Codes (DTCs).
- ✔ Check Engine Light is on with codes like P0601, P0606, or U0100.
- ✔ Vehicle has trouble starting or won’t start at all.
- ✔ Noticeable loss of engine power and acceleration.
- ✔ Poor or erratic automatic transmission shifting.
- ✔ A significant drop in fuel economy for no apparent reason.
- ✔ Engine stalling or misfiring intermittently.
- ✔ Communication issues with diagnostic scan tools.
A Straightforward Guide to Installation
Installing your pre-programmed 2014-2016 ELR Engine Control Module is a manageable job for a DIY enthusiast or a quick task for any professional mechanic. Our VIN programming makes this a true plug-and-play repair.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait a few minutes to ensure the system is fully discharged.
- Locate the Module: On the Cadillac ELR and Volt, the ECM is found in the left-hand (driver’s side) rear of the engine compartment. On trucks like the Silverado or vans like the Express, 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. Most have locking tabs that need to be released. Once disconnected, unbolt the old module from its mounting bracket.
- Install the New ECM: Mount the new module securely onto the bracket and firmly reconnect the electrical harnesses. Ensure they click into place to establish a solid connection.
- Reconnect Power: Reattach the negative battery terminal.
- Perform Security Relearn: Some GM vehicles may require a simple security relearn procedure to sync the new ECM with the anti-theft system. This can typically be done without special tools by cycling the key in the ignition. Instructions are readily available online for your specific model.
Verified Vehicle Compatibility for Part 12643636
This Engine Control Module is a direct replacement for a wide range of General Motors vehicles. It is compatible with original part numbers 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200. Please verify your vehicle from the list below.
- Cadillac ELR 2014-2016
- Chevrolet Cruze 2012-2016 (1.4L & Gasoline models)
- Chevrolet Sonic 2012-2016 (1.4L)
- Chevrolet Spark 2014-2015 (Gasoline)
- Chevrolet Trax 2013-2016
- Chevrolet Volt 2011-2015
- Buick Encore 2013-2016 (1.4L)
- Chevy Express 2500/3500 Van 2016 (4.8L, 6.0L)
- GMC Savana 2500/3500 Van 2016 (4.8L, 6.0L)
- Chevy Silverado 2500/3500 Pickup 2012-2016 (6.0L)
- GMC Sierra 2500/3500 Pickup 2012-2016 (6.0L)
- GMC Sierra Denali 2500/3500 2012-2016 (6.0L)
- Chevrolet Suburban 3500 2016
Frequently Asked Questions
Do I need to have this module programmed by a dealer?
No. We handle the programming for you before we ship. We use your VIN to load the latest GM software, so it’s ready for installation when you receive it.
Where do I provide my VIN?
After you complete your purchase, you will need to send us your 17-digit VIN. We will provide clear instructions on how to do this. We cannot ship the module until we have programmed it.
Is this a difficult part to install?
For most models, this is a direct bolt-in replacement that requires basic hand tools. The most important part is ensuring the electrical connectors are seated properly. Many DIYers can complete the job in under an hour.
My original part number is different. Will this still work?
Yes, this module replaces several part numbers, including 12668866, 12668994, and others listed above. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.
What is a security relearn procedure?
It’s a simple sequence, usually involving turning the key to the ‘ON’ position for 10-15 minutes, that allows your vehicle’s anti-theft system to recognize the new ECM. It does not require any special scan tools.