Is Your Sierra Denali Running Rough or Refusing to Start?
If you’re dealing with a persistent check engine light, erratic engine behavior, poor fuel economy, or even a no-start condition in your 2012-2016 Sierra Denali 2500, a failing Engine Control Module (ECM) is a very likely culprit. As the central computer for your truck’s engine, when the ECM begins to fail, it can create a cascade of frustrating and difficult-to-diagnose problems. This isn’t just an inconvenience; it’s a critical component failure that compromises your truck’s reliability and performance.
This replacement Engine Control Module, part number 12668991, is the definitive solution to restore your truck’s factory operation. We take the guesswork and high cost out of the repair by programming the module specifically to your truck’s Vehicle Identification Number (VIN) before it ships. This means it arrives at your door loaded with the latest official GM software updates, ready for a straightforward installation without requiring an expensive trip to the dealership for programming.
Common Symptoms of a Failing GM ECM:
- โ Persistent Check Engine Light (CEL) with various trouble codes.
- โ Engine stalling, stumbling, or misfiring unexpectedly.
- โ Noticeable decrease in fuel efficiency.
- โ Harsh or incorrect shifting from the transmission.
- โ Complete no-start or intermittent starting issues.
- โ Communication errors with diagnostic scan tools.
Real-World Diagnosis: “A customer’s 2014 Sierra 2500 came into my shop last month with what seemed like a classic throttle body problemโerratic idle and a P2135 code. He had already replaced the throttle body assembly twice with no luck. After confirming the new parts were good, we scoped the circuits at the ECM. We found the 5-volt reference signal from the module was dropping out intermittently. The issue wasn’t the sensor; it was the ECM’s internal driver circuit failing under load. We installed a VIN-programmed module just like this one, performed the throttle relearn, and the truck has run perfectly ever since. It’s a common misdiagnosis that costs people time and money on unnecessary parts.”
Plug-and-Play Installation: No Dealer Visit Required
Our VIN programming service makes this a job you can confidently do yourself. By matching the software to your specific truck, we eliminate the need for dealer-level tools. Follow these general steps to get your Sierra back on the road:
- Safety First: Disconnect the negative terminal from your truck’s battery and secure it away from the post.
- Locate the ECM: On your Sierra 2500, the ECM is typically found in the engine bay on the driver’s side, near the firewall or fuse box.
- Disconnect Connectors: Carefully release the locking tabs and unplug the large electrical connectors from the old module. Inspect the pins for any corrosion or damage.
- Remove Old Module: Unbolt the old ECM from its mounting bracket.
- Install New Module: Mount the new, pre-programmed ECM in place and securely fasten it.
- Reconnect: Plug the electrical connectors firmly into the new module until they click into place.
- Power Up: Reconnect the negative battery terminal. A security or throttle position relearn procedure may be required, which can typically be done without special tools (instructions are widely available or can be provided).
Guaranteed Compatibility for Your 2012-2016 Sierra Denali 2500 Engine Control Module
This module is a direct replacement for a wide array of GM vehicles, ensuring a perfect fit and function. It is the correct part for your 2012-2016 Sierra Denali 2500 with the 6.0L engine and directly interchanges with the following part numbers:
Interchangeable Part Numbers: 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, 12692200.
While this is the primary ECM for the Sierra/Silverado HD trucks and Express/Savana vans, its versatile architecture means it’s also the correct module for many other GM cars and SUVs. By providing your VIN, you guarantee we will load the exact software your vehicle requires. Don’t let a faulty computer keep your powerful truck sidelined. Order today and restore the performance and reliability you depend on.