Is Your 6.6L Duramax Running Rough?
If your 2013-2014 GMC Sierra, Chevy Silverado, or GM Express/Savana van with the 6.6L Duramax diesel engine is experiencing frustrating issues like a persistent check engine light, poor fuel economy, erratic shifting, or even a no-start condition, a failing Engine Control Module (ECM) could be the culprit. The ECM is the central computer of your truck, responsible for managing everything from fuel injection and ignition timing to emissions controls and transmission function. When it fails, it can cause a wide range of problems that can leave you stranded.
This listing is for a genuine, used GM Engine Control Module, part number 12654088 (also fits service number 12653319). We take the guesswork and high cost out of the repair process. Instead of buying a blank module and paying a dealership hundreds for programming, we flash this unit with the latest official GM software specifically matched to your truck’s Vehicle Identification Number (VIN) before it ships. This ensures compatibility and proper function right out of the box.
From the Diagnostic Bay
We had a 2013 Silverado 3500 tow rig come in with a maddeningly intermittent no-start problem. It would crank but wouldn’t fire, with no check engine light and no codes stored. After hours of chasing wires and checking sensors, we hooked up our high-level scan tool and found the ECM would occasionally drop communication entirely. The internal processor was failing. We sourced a quality used module, programmed it to the truck’s VIN, performed the quick security relearn, and the truck fired up instantly. The customer was back on the road to the job site the same day, having avoided a massive dealership bill and a long wait for a new part.
Common Symptoms of a Failing GM 6.6L ECM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes.
- ✔ Vehicle refuses to start or stalls unexpectedly.
- ✔ Noticeable decrease in engine power and acceleration.
- ✔ Poor fuel mileage and rough idling.
- ✔ Harsh or incorrect automatic transmission shifting.
- ✔ Communication errors with diagnostic scan tools.
- ✔ Issues with other electronic modules due to network problems.
Why Choose Our Programmed 2013-2014 Sierra 2500 ECM?
Getting your heavy-duty truck back to work is our top priority. This isn’t just a used part; it’s a complete, plug-and-play solution designed to save you time and money. Each module is sourced from a salvaged vehicle and carefully inspected. The real value is in our professional programming service. We use the same tools as the dealership to load your vehicle’s specific calibration files and the newest software updates from GM. This process ensures all systems operate as the factory intended, restoring lost performance and efficiency.
Important Installation Information
While we handle the complex VIN-specific programming, one final step is required upon installation: the Vehicle Theft Deterrent System (VTDS) relearn. This is a security handshake procedure that pairs the new ECM to your truck’s ignition and security system. Without it, the vehicle will not start. This procedure must be performed using a professional-grade scan tool with GM programming capabilities (like TIS2Web). This is a standard step for any ECM replacement on these vehicles. Other procedures, such as a crankshaft position variation relearn or injector flow rate programming, may also be necessary depending on your vehicle’s specific condition and any stored trouble codes. This is the responsibility of the installer.
Frequently Asked Questions
Do I need to get this ECM programmed by a dealer?
No. We handle all the programming for you before we ship the part. Simply provide us with your vehicle’s 17-digit VIN during or after checkout, and we will flash the module with the correct GM software for your truck.
What is a ‘theft relearn’ and is it difficult?
A theft relearn is a security procedure that syncs the replacement ECM to your vehicle’s anti-theft system. It is a mandatory step. It is not difficult for a qualified technician with the proper GM-compatible diagnostic tools, and typically takes only a few minutes to complete.
Is this a new part?
No, this is a high-quality, tested, and fully functional used part sourced from a salvaged vehicle. This allows us to provide a cost-effective solution for your repair needs.
What information do you need from me?
We need your vehicle’s complete 17-digit VIN to ensure we load the exact correct software and calibration files for your specific model, year, and options.
Will this ECM fit my 2014 Chevy Express Van?
Yes, this ECM fits a wide range of 2013-2014 GM trucks and vans equipped with the 6.6L Duramax engine, including the Sierra 2500/3500, Silverado 2500/3500, and Express/Savana 2500/3500. Please verify the part number 12654088 matches your original unit.