Is Your GM Vehicle Running Rough? The Engine’s Brain Might Be the Cause.
As a technician with over two decades of experience under the hood, I’ve seen it all. A customer comes in with a vehicle that’s stalling, shifting erratically, or just has no power. They’ve replaced sensors, checked wiring, but the check engine light remains stubbornly on. More often than not, the culprit is the Engine Control Module (ECM)—the central computer that manages everything from fuel injection to spark timing. When it fails, it can cause a cascade of frustrating and hard-to-diagnose problems. This isn’t just a part; it’s the command center for your engine’s performance and reliability.
This replacement ECM is the definitive solution for a wide range of GM cars, trucks, and SUVs. What sets our service apart is that we take the biggest headache out of the equation: programming. Simply provide your vehicle’s VIN at checkout, and my team will flash this module with the latest, factory-correct GM software specifically for your vehicle. This means it arrives at your door ready for installation, saving you a costly trip to the dealership and hours of diagnostic guesswork. This is the same process we use in our own shop to get customers back on the road with confidence.
Common Signs of a Failing Engine Computer
If you’re experiencing any of the following, a faulty ECM is a likely cause. I’ve personally traced these symptoms back to a failing module on hundreds of GM vehicles.
- ✔ Unexplained Check Engine Light with codes like P0601, P0606, or other internal processor faults.
- ✔ Vehicle refuses to start or has intermittent starting issues.
- ✔ A noticeable drop in fuel economy.
- ✔ Engine stalling, misfiring, or running rough.
- ✔ Problems with the automatic transmission shifting smoothly.
- ✔ Communication errors with other modules (U-codes).
A Technician’s Notebook
I remember a 2017 Sierra 1500 that came into the bay with a ghost of a problem. It would randomly lose power on the highway, but no codes were stored. The owner had spent a fortune at other shops. After running a full diagnostic, we noticed the ECM’s live data stream would occasionally freeze for a split second. It was a classic sign of internal failure. We installed one of these VIN-programmed modules, performed the crankshaft and theft relearn procedures, and the truck has run flawlessly ever since. Getting it pre-programmed saved the customer at least two hours of shop labor and the hassle of a tow to the dealer.
Your Straightforward Installation Guide
Installing your new 2017 ATS Engine Control Module is manageable for a DIY enthusiast or a quick job for any professional. Follow these general steps to ensure a smooth process.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the ECM: On most listed models, the ECM is found in the engine compartment (often on the driver’s side) or, on the Corvette, under the passenger-side cowl. Check your service manual for the exact location.
- Disconnect and Remove: Carefully unplug the electrical connectors. Most have a locking tab that needs to be released. Once disconnected, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed ECM into place. Reconnect the electrical harnesses, ensuring they click securely into place.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Relearn Procedures: This is a critical final step. You will need access to a GM diagnostic tool (like Tis2web/Techline Connect) to perform the Vehicle Theft Deterrent System relearn. The vehicle may not start until this is completed. Other procedures, like a crankshaft variation relearn, may also be necessary depending on your specific vehicle. This is the responsibility of the installer.
Guaranteed Vehicle Compatibility
This module is a direct replacement for part number 12674052 and interchanges with 12692068, 12704476, 12686382, 12674472, and 12678815. It is verified to fit the following vehicles:
- ✔ 2017 Cadillac ATS (3.6L, VIN Y, opt LF4)
- ✔ 2017 Cadillac CTS (6.2L Supercharged or 3.6L Twin Turbo VIN 8, opt LF3)
- ✔ 2017 Cadillac Escalade & Escalade ESV
- ✔ 2017 Cadillac XTS (3.6L, VIN 8, opt LF3)
- ✔ 2017 Chevrolet Corvette
- ✔ 2016-2018 Chevrolet Silverado 1500 Pickup
- ✔ 2017 Chevrolet Suburban 1500
- ✔ 2017 Chevrolet Tahoe
- ✔ 2016-2018 GMC Sierra 1500 & Sierra Denali 1500
- ✔ 2017 GMC Yukon & Yukon XL 1500
Frequently Asked Questions
Why do I need to provide my VIN?
Your Vehicle Identification Number (VIN) is essential for us to program the ECM with the exact software and calibrations your vehicle requires from the factory. This ensures proper engine function, transmission control, and compatibility with your vehicle’s specific options.
What is a theft relearn and why is it required?
The Vehicle Theft Deterrent System (VTDS) pairs your ECM to your vehicle’s ignition and security system. When you install a new ECM, the system sees it as a potential theft attempt and prevents the engine from starting. The relearn procedure uses a professional scan tool to sync the new ECM, telling the vehicle it’s an authorized part.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the ECM (common codes include P0601-P0606), then yes, this part will resolve the issue. However, you must ensure the root cause of the problem is the ECM and not a faulty sensor or wiring issue elsewhere.
Can I install this myself if I’m not a mechanic?
The physical installation is straightforward for many DIYers. However, the final, mandatory step involves relearn procedures that require a professional-grade GM diagnostic tool. We recommend this part for experienced DIYers who have access to such tools or for professional repair shops.
What other part numbers does this ECM replace?
This module is a direct, compatible replacement for several GM part numbers, including 12692068, 12704476, 12686382, 12674472, and 12678815, in addition to 12674052.