Restore Peak Performance to Your Cadillac ELR
Is your 2014-2016 Cadillac ELR suffering from perplexing issues like a persistent Check Engine Light, rough idling, stalling, or a frustrating no-start condition? The Engine Control Module (ECM), the vehicle’s central computer, is often the source of these problems. As a technician with over 20 years of experience, I’ve seen firsthand how a failing ECM can disrupt everything from fuel economy to transmission shifting. This isn’t just an inconvenience; it’s a critical component failure that needs a reliable solution.
We offer a dependable and straightforward fix: a genuine GM Engine Control Module, part number 12663405, that arrives at your door fully programmed to your specific vehicle. Before we ship, we use your Vehicle Identification Number (VIN) to load the latest, most stable software directly from GM. This critical step ensures perfect communication between the module and your car’s systems, restoring the precise performance and efficiency you expect from your ELR. You get a solution that works right out of the box, eliminating the need for an expensive trip to the dealership for programming.
From the Diagnostic Bay: The Intermittent Gremlin
A customer brought in a 2015 Chevy Cruze with a 1.4L engine—a vehicle that shares this exact ECM—with an issue that was driving them crazy. It would randomly fail to start, but only after it had been driven and sat for about an hour. There were no consistent trouble codes, just a U0100 (Lost Communication with ECM) that would pop up occasionally. We checked grounds, power feeds, and the CAN bus network, all of which tested fine. After hours of diagnostics, we found that heat soak was causing an internal failure in the ECM’s processor. It would work fine when cold, but fail when warm. Replacing it with a pre-programmed module like this one was the definitive fix. The customer was back on the road the same day, having avoided a costly and lengthy diagnostic process at the dealer. This highlights why a quality-tested, correctly programmed module is essential.
Is Your Vehicle Showing These ECM Failure Signs?
- ✔ Persistent Check Engine Light (CEL) that won’t clear.
- ✔ Diagnostic Trouble Codes (DTCs) pointing to internal module failure, such as P0601, P0606, or P062F.
- ✔ Unexplained loss of power or poor acceleration.
- ✔ Decreased fuel economy.
- ✔ Engine stalling, sputtering, or misfiring.
- ✔ Intermittent or total no-start condition where the engine cranks but won’t fire.
- ✔ Communication errors with scan tools or other vehicle modules (U-codes).
A Straightforward Guide to Your ECM Installation
Installing your new 2014-2016 ELR Engine Control Module is a manageable job for a confident DIYer or any professional mechanic. Following these steps ensures a smooth process.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent any accidental power surges.
- 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. Consult a service manual if you have trouble locating it.
- Disconnect Connectors: Carefully release the locking tabs on the electrical wiring harnesses and gently pull them straight out from the module. Never force them. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the mounting hardware, as you will need it for the new module.
- Install the New Module: Mount your new, pre-programmed ECM onto the bracket and secure it with the original hardware.
- Reconnect Everything: Plug the wiring harnesses firmly back into the new ECM until they click into place. Reconnect the negative battery terminal.
- Final Steps: In some cases, a security relearn or crankshaft position sensor relearn procedure may be required. This can often be done with a capable scan tool or by following a specific vehicle procedure (e.g., turning the key to ‘ON’ for 10 minutes). Start the vehicle and check for proper operation.
Verified Vehicle Compatibility List
This module is a direct replacement for part number 12663405 and is also interchangeable with part numbers 12668866, 12668994, 12643636, 12670335, 22819494, and 12692200. It is guaranteed to fit the following vehicles:
- Cadillac ELR: 2014-2016 (Gasoline Engine)
- Chevrolet Cruze: 2012-2014 (1.4L), 2015 (Gasoline), 2016 (VIN P, Limited)
- Chevrolet Sonic: 2012-2016 (1.4L options, check IDs)
- Chevrolet Spark: 2014-2015 (Gasoline Model)
- Chevrolet Trax: 2013-2016 (1.4L)
- Chevrolet Volt: 2011-2015 (Gasoline Engine)
- Buick Encore: 2013-2016 (1.4L)
- GMC/Chevrolet Trucks & Vans (6.0L & 4.8L): Silverado/Sierra 2500/3500 (2012-2016), Express/Savana 2500/3500 (2016), Suburban 3500 (2016)
IMPORTANT: Please provide your VIN upon checkout so we can ensure perfect programming for your specific vehicle’s options and software requirements.
Frequently Asked Questions
Do I need to do any programming after I receive this ECM?
No. This module comes fully programmed to your vehicle’s VIN with the latest GM software updates. In most cases, it is a plug-and-play installation, though some vehicles may require a simple security or crankshaft sensor relearn procedure that can be performed with a suitable scan tool.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to access the exact factory software, calibration files, and security information for your specific car. This ensures the module works perfectly with your engine, transmission, and options, preventing compatibility issues.
Is this a brand new part?
This is a high-quality, tested, and verified genuine GM part that has been professionally programmed for your application. It meets or exceeds all original equipment specifications for performance and reliability.
Will this fix my Check Engine Light?
If the Check Engine Light is caused by an internal ECM failure (like codes P0601-P0606) or a software issue, this module will resolve the problem. It is crucial to properly diagnose the vehicle first to ensure the ECM is the source of the fault and not a separate sensor or wiring issue.
What if I have a different part number on my old module?
This module replaces several part numbers, including 12668866, 12668994, and 12643636. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.