Restore Your Cadillac’s Performance and Reliability
The Engine Control Module (ECM), often called the engine’s brain, is the central command center for your 2017-2019 Cadillac XTS. It meticulously manages critical functions like fuel injection, ignition timing, emissions systems, and transmission shifting to ensure your 3.6L LFX engine operates with the precision and power you expect. When this vital component begins to fail, it can lead to a cascade of frustrating and potentially damaging issues, from poor fuel economy and rough idling to a complete no-start situation. This replacement ECM, part number 12667189, is the definitive solution to restore your vehicle’s factory performance and get you back on the road with confidence.
The Critical Role of a Programmed 2017-2019 XTS ECM
Unlike many other automotive parts, an ECM is not a simple ‘plug-and-play’ component. Each module is programmed with vehicle-specific software that corresponds to your car’s unique Vehicle Identification Number (VIN). This software accounts for your specific options, emissions standards, and security systems. Installing a non-programmed module will result in a vehicle that won’t start or run correctly. We eliminate this complexity by pre-programming this ECM to your exact VIN before it ships. This ensures a seamless installation process, allowing the new module to communicate perfectly with all other systems in your Cadillac XTS, just as the original did.
From the Diagnostic Bay
We had a 2018 XTS come into the shop with a bizarre, intermittent stalling problem. The owner had been to two other shops that couldn’t pinpoint the issue. There were no consistent trouble codes, just a vague U0100 ‘Lost Communication with ECM’ code that would pop up sporadically. We checked all the wiring, grounds, and power feeds to the ECM, and everything looked perfect. On a hunch, we monitored the 5-volt reference circuits from the ECM while the engine was running. After about 20 minutes, we saw the voltage flicker and drop, causing the engine to stumble and die. The ECM was failing internally under heat soak. We installed one of our VIN-programmed modules, and the car ran flawlessly. It’s a classic example of how a failing ECM can create ghost-like problems that are nearly impossible to trace without seeing it happen before.
Common Symptoms of a Failing XTS ECM
- ✔ Unexplained Check Engine Light illumination
- ✔ Engine stalling, stumbling, or misfiring
- ✔ Drastic decrease in fuel efficiency
- ✔ Car refuses to start, even with a good battery and starter
- ✔ Harsh or erratic automatic transmission shifting
- ✔ Communication errors with diagnostic scan tools
- ✔ Loss of power or sluggish acceleration
A Straightforward Solution for a Complex Problem
Don’t let a faulty engine computer keep your luxury sedan parked. Our process is designed to be simple and effective. Once you purchase this module, simply provide us with your vehicle’s VIN. Our technicians will then flash the unit with the latest GM-certified software specific to your car. This ensures all parameters are set correctly for your engine and transmission. The module you receive will be ready for installation, often only requiring a simple security relearn procedure which can be performed without any special tools. This part is a direct replacement for part numbers 12667002, 12666070, and 12667189, guaranteeing a perfect fit and function for your 2017-2019 XTS ECM and other compatible GM vehicles.
Frequently Asked Questions
Do I need to do anything after installing this ECM?
In most cases, you will need to perform a security relearn procedure, also known as a key relearn. This procedure syncs the new ECM with your vehicle’s anti-theft system and can typically be done in your driveway in about 30 minutes without any special tools. Instructions are readily available online or in your vehicle’s service manual.
How do I provide my VIN number?
After completing your purchase, you can send us a message with your 17-digit VIN. We cannot program and ship the module without this information, so please provide it promptly to avoid delays.
Is this a brand new part?
This is a high-quality, tested, and verified used OEM part. Each unit is inspected and then programmed with the latest software for your vehicle, ensuring reliable performance and compatibility.
Will this fix my car’s problem for sure?
While this module will fix issues directly caused by a faulty ECM, it’s crucial to ensure your vehicle has been properly diagnosed. This part will not solve problems related to bad sensors, faulty wiring, or mechanical failures. We recommend a professional diagnosis if you are uncertain.
Where is the ECM located on my 2017-2019 Cadillac XTS?
On the Cadillac XTS with the 3.6L engine, the ECM is typically located in the engine compartment. Always disconnect the battery before attempting to remove or install the module.