Get Your Sierra Running Right Again
Is your 2012-2016 Sierra 2500 acting up? If you’re dealing with frustrating issues like a persistent check engine light, poor fuel economy, stalling, or rough running, the problem often points directly to a failing Engine Control Module (ECM). As a technician with over two decades of experience under the hood, I’ve seen firsthand how a faulty ECM can cripple even the toughest trucks. It’s the brain of your engine, and when it’s not working correctly, nothing else will.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We take a genuine GM Engine Control Module (interchangeable with part numbers 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200) and professionally program it with the very latest GM-certified software. All we need is your truck’s Vehicle Identification Number (VIN) at checkout. This ensures the module is a perfect match for your vehicle’s specific configuration, restoring its original performance and efficiency without a costly trip to the dealership for programming.
A Technician’s Notebook: The Intermittent Stall
A customer brought in his ’14 Sierra 2500 with the 6.0L. The complaint was a ghost: it would randomly stall at stoplights, but never stored a clear trouble code. We checked fuel pressure, sensors, and wiring—everything looked perfect. After days of diagnostics, I noticed the data stream from the ECM would flicker just before a stall. We swapped in one of these pre-programmed modules, and the problem vanished instantly. The original ECM had an internal processor fault that only showed up under specific thermal conditions. This solution saved the customer hundreds in diagnostic labor and got his work truck back on the road reliably.
Is Your Truck Showing These Symptoms?
A failing ECM can manifest in many ways. If you’re experiencing any of the following, this module is the likely solution for your 2012-2016 Sierra 2500 ECM issues.
- ✔ Check Engine Light is on with no obvious cause.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0601 (Internal Control Module Memory Check Sum Error), P0606 (ECM/PCM Processor Fault), or U0100 (Lost Communication With ECM/PCM).
- ✔ The engine cranks but refuses to start.
- ✔ Noticeable decrease in fuel mileage.
- ✔ The engine stalls, hesitates, or runs rough.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Failure to pass an emissions test.
A Straightforward Guide to Installation
Replacing the ECM on your Sierra is a job most DIYers can handle in their own driveway. Our VIN-programming service makes it a direct-fit process.
- Safety First: Disconnect the negative terminal from your truck’s battery.
- Locate the ECM: On the 2012-2016 Sierra 2500, the ECM is located in the front left (driver’s side) of the engine compartment.
- Disconnect the Harnesses: Carefully release the locking tabs and unplug the main electrical connectors from the old module.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed ECM into place and securely reconnect the electrical harnesses.
- Reconnect the Battery: Re-attach the negative battery terminal.
- Perform Security Relearn: In some cases, you may need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes. Consult your owner’s manual for the exact steps for your vehicle.
Verified Vehicle Compatibility
This module is a guaranteed fit for the 6.0L V8 engine in the following heavy-duty trucks and is also a direct replacement for numerous other GM vehicles that use the same part number. Please verify your part number before ordering.
- SIERRA 2500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
- SIERRA 3500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
- SILVERADO 2500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
- SILVERADO 3500 PICKUP 12-16 Electronic Control Module; (LH front engine compartment), 6.0L
- EXPRESS/SAVANA 2500 & 3500 VANS 16 Electronic Control Module; (LH rear engine compartment), 4.8L or 6.0L
- SUBURBAN 3500 16 Electronic Control Module; (LH front engine compartment)
- This module also fits a wide range of other GM vehicles including the Cruze, Sonic, Trax, Encore, Volt, ELR, and Spark from various years. Cross-reference your original part number (e.g., 12643636, 12668866) to ensure compatibility.
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to program the Engine Control Module with the exact software and calibrations specified by GM for your truck’s engine, transmission, and options. This ensures perfect compatibility and performance.
Is this a plug-and-play part?
Yes, because we program it to your VIN, it is designed to be a direct replacement. In some instances, a simple, key-on security relearn procedure may be required, which does not need any special tools.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the ECM (like codes P0601 or P0606), this part will be the correct fix. It is always best to have the codes professionally diagnosed to ensure the ECM is the root cause.
Where is the part number on my old ECM?
The part number is typically found on a white sticker on the case of your existing Engine Control Module. It will be a multi-digit number, such as 12643636.
What if I have a different engine than the 6.0L?
This ECM fits a wide variety of GM vehicles with different engines. The critical factor is matching the service part number from your original module to one of the numbers listed, such as 12643636, 12668866, or 12670335.