Is Your Sierra 3500 Suddenly Unreliable?
You rely on your truck to work as hard as you do. But when the Engine Control Module (ECM) starts to fail, it can bring your entire operation to a halt. Are you experiencing baffling symptoms like a random no-start, the engine cranking but not firing, erratic shifting, a persistent Check Engine Light with a slew of communication codes, or a truck that runs rough and guzzles fuel? These are classic signs that the brain of your engine has given up.
Just last week, a 2014 Sierra 3500 work truck was towed into my bay. The owner was at his wit’s end โ it would crank but not start, and when it did, it ran terribly and threw a half-dozen codes my scanner couldn’t even make sense of at first. After confirming the fuel and ignition systems were mechanically sound, all diagnostics pointed to an internal ECM failure. This is a scenario I’ve seen dozens of times on these hard-working GM trucks.
The Direct-Fit, Programmed Solution for Your Truck
Don’t let a faulty computer keep you sidelined. This Engine Control Module is the definitive solution for your 2012-2016 Sierra 3500. The biggest hurdle with replacing an ECM is the expensive and time-consuming programming required at a dealership. We eliminate that step entirely. When you order from us, you simply provide your vehicle’s VIN, and our technicians will flash this module with the latest, most stable GM-approved software specific to your truck. It arrives at your door ready to install.
Expert Pro Tip: Check Your Connections
Before you plug in your new ECM, take a flashlight and carefully inspect the harness connectors. Over the years, I’ve seen countless jobs where bent pins or green corrosion from moisture intrusion caused the original failure. A quick spray with electronics contact cleaner and a gentle check of the pins can prevent a repeat failure and ensure a solid, lasting connection for your new module.
Why Choose Our 2012-2016 Sierra 3500 ECM?
This isn’t just a replacement part; it’s a restoration of your truck’s core functionality. By installing a properly programmed ECM, you’re not just clearing codesโyou’re ensuring the engine and transmission are communicating correctly for optimal power, efficiency, and longevity.
- โ VIN-Programmed for You: Arrives with the latest GM software, matched specifically to your truck.
- โ No Dealer Required: Save hundreds of dollars and the headache of scheduling a dealer appointment for programming.
- โ Solves Common Failures: Directly addresses issues like no-start, poor performance, and communication error codes (U-codes).
- โ Restores Performance: Get back the smooth idle, crisp throttle response, and proper shifting you expect.
- โ Broad Compatibility: This module also serves as a direct replacement for a wide range of other GM vehicles (see fitment list).
Plug-and-Play Installation: Get Back on the Road Fast
You don’t need to be a master technician to complete this job. With basic tools, you can have your truck running right in under an hour.
- Safety First: Disconnect the negative terminal from your truck’s battery.
- Locate the ECM: On the Sierra 3500, it’s typically found in the LH front of the engine compartment.
- Disconnect Connectors: Carefully unlatch and remove the wiring harness connectors from the old module.
- Unbolt the Old Unit: Remove the mounting bolts holding the old ECM in place and take it out.
- Install the New ECM: Mount your new, pre-programmed module and secure it with the bolts.
- Reconnect and Finalize: Plug the harness connectors firmly into the new ECM, then reconnect your battery terminal. In some cases, a simple security relearn procedure may be required, which can be done without special tools.
Replaces Multiple Part Numbers:
This module is a direct replacement for part numbers: 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200.