Restore Peak Performance to Your GM Truck or SUV
Is your Silverado, Sierra, or other GM vehicle suffering from frustrating, hard-to-diagnose issues? A faulty Engine Control Module (ECM) is often the hidden culprit behind problems like a no-start condition, erratic engine behavior, poor fuel economy, or a persistent Check Engine Light with multiple communication codes. As a technician with over two decades of experience, I’ve seen firsthand how a failing ECM can mimic a dozen other problems, leading to wasted time and money on incorrect repairs. This module, part number 12678815, is the definitive solution to get your vehicle running reliably again.
We take the guesswork out of the repair. Unlike a generic module from a parts store, this ECM arrives at your door pre-programmed with the latest official GM software, specifically matched to your vehicle’s VIN. This critical step ensures all factory settings and operational parameters are correct from the moment of installation, restoring the precise performance and efficiency your vehicle was designed for.
Case Study: A Tricky Diagnosis
A 2017 Sierra 1500 came into the bay with a complaint of intermittent stalling and a whole cluster of unrelated warning lights. The owner had already replaced the battery and alternator. Scans showed communication loss codes (U0100) and a random throttle body code (P2101). Instead of chasing ghosts, we went straight to the source. We checked the power and ground feeds to the ECM, which were solid. Swapping in a known-good, programmed ECM like this one resolved all issues instantly. The original module’s internal processor was failing under load, a common issue I’ve seen on dozens of these E92 controllers. This part saved the customer from hundreds more in unnecessary diagnostic labor.
Is Your Truck Showing These Symptoms?
- ✔ Check Engine Light is on with codes like P0601, P0606 (Internal Control Module Failure), or U-series communication codes.
- ✔ The engine cranks but will not start.
- ✔ Noticeable decrease in fuel mileage.
- ✔ The transmission shifts harshly or at the wrong times.
- ✔ Stalling, hesitation, or rough idling for no apparent reason.
- ✔ Unexplained loss of power and poor acceleration.
A Straightforward Guide to Installation
Replacing your 2016-2018 Silverado 1500 ECM is a manageable job for a confident DIYer or any professional mechanic. Following these steps ensures a smooth process.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Locate the ECM: On most GM trucks like the Silverado and Sierra, the ECM is located in the engine compartment on the driver’s side, near the firewall or airbox.
- Disconnect Connectors: Carefully release the locking tabs on the wiring harness connectors and pull them straight out from the module. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. It’s typically held in place by a few 10mm bolts.
- Install the New ECM: Mount your new, pre-programmed ECM onto the bracket and secure the bolts.
- Reconnect Everything: Firmly plug the wiring harness connectors back into the new module until they click into place. Reconnect the negative battery terminal.
- Perform Relearn Procedures: This is a critical final step. The vehicle’s theft deterrent system must be synchronized with the new ECM. This typically requires a scan tool with pass-thru capabilities and a subscription to GM’s TIS2Web/Techline Connect. Other procedures, like a Crankshaft Position Variation Relearn, may also be necessary. This is the responsibility of the installer.
Will This Fit My Vehicle?
This Engine Control Module is a direct-fit replacement for a wide range of GM vehicles. Please verify your part number or contact us with your VIN to confirm compatibility. This module is compatible with part numbers 12692068, 12704476, 12686382, 12674052, 12674472, and 12678815 and fits the following models:
- 2017 Cadillac Escalade & Escalade ESV
- 2017 Cadillac XTS (3.6L Twin Turbo LF3)
- 2017 Cadillac CTS (6.2L Supercharged & 3.6L Twin Turbo LF3)
- 2017 Cadillac ATS (3.6L Twin Turbo LF4)
- 2017 Chevrolet Corvette
- 2017 Chevrolet Tahoe & Suburban 1500
- 2016-2018 Chevrolet Silverado 1500 Pickup
- 2017 GMC Yukon & Yukon XL 1500
- 2016-2018 GMC Sierra 1500 Pickup
- 2017-2018 GMC Sierra Denali 1500
Frequently Asked Questions About This ECM
Do I need to do anything after I install this ECM?
Yes. After installation, you or your mechanic must perform a Vehicle Theft Deterrent Relearn using a GM-compatible programming system (like TIS2Web/Techline Connect). Other relearns, such as for the crankshaft position sensor, may also be required depending on your vehicle. This is a standard procedure when replacing a modern ECM.
How do I provide my VIN for programming?
After you complete your purchase, simply send us a message with your vehicle’s 17-digit VIN. We will program the module with the latest GM software for your specific vehicle before we ship it out.
Is this a used part?
This is a high-quality, tested, and verified OEM part that has been expertly programmed for your specific application. It’s guaranteed to restore function to your vehicle’s engine management system.
What if my part number is slightly different?
This module replaces several part numbers, including 12692068, 12704476, 12686382, and others listed. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.
Will this fix my specific problem?
This part is the solution for a failed ECM. If your vehicle has been properly diagnosed with a faulty Engine Control Module (e.g., internal processor error codes P0601-P0606), this will resolve the issue. It will not fix problems caused by other faulty components like sensors or wiring.