Is Your GM 6.6L Duramax Running Rough? Get Back on the Road Fast.
If you’re dealing with frustrating engine problems on your 2013-2014 GM truck or vanโlike a no-start condition, erratic performance, or a persistent Check Engine Light that won’t go awayโa faulty Engine Control Module (ECM) is a very common culprit. As the brain of your powerful 6.6L Duramax diesel engine, a failing ECM can cause a cascade of issues that are often misdiagnosed. This is a reliable, tested, and correctly programmed replacement ECM, part number 12654088, ready to restore your vehicle’s performance and reliability.
Expert Pro Tip: Don’t Chase Ghosts in the Machine
In my 20+ years of diagnostics, I’ve seen countless technicians and DIYers replace expensive injectors, sensors, and even high-pressure fuel pumps, only to find the root cause was the ECM itself. A classic sign I look for is intermittent communication loss with the scan tool or multiple, unrelated trouble codes appearing at once. Before you spend another dime on parts, consider if the central computer is the real issue. This module can save you hundreds, if not thousands, in unnecessary repairs.
The Smart Solution: VIN-Programmed for Your Vehicle
Forget the hassle and high cost of a dealership visit. We take the guesswork out of the repair. Simply provide us with your vehicle’s 17-digit VIN during checkout, and our technicians will flash this module with the latest, most stable GM factory calibrations specific to your exact truck or van. This ensures perfect communication with your transmission, instrument cluster, and emissions systems.
Common Symptoms of a Failing 2013-2014 Express 2500 ECM:
- โ Complete no-start or crank-no-start condition.
- โ Check Engine Light is on with various communication or sensor codes.
- โ Poor fuel economy and noticeable loss of power.
- โ Engine stalling or running rough intermittently.
- โ Transmission shifting issues or harsh engagement.
- โ Inaccurate gauge readings or warning lights.
Installation and Setup Requirements
This is a used ECM sourced from a salvaged vehicle, inspected for quality and function. While our programming handles the core software, a few final setup procedures are the responsibility of the installer. This is standard for any ECM replacement on these GM platforms.
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Provide Your VIN:
After your purchase, please send us your vehicle’s VIN. We cannot ship the module until it is programmed. -
Physical Installation:
Disconnect the battery. Locate and replace the old ECM. On Express/Savana vans, it’s typically on the lower left (driver’s) side of the engine compartment. On Sierra/Silverado pickups, it’s on the upper left (driver’s) side, near the firewall. -
CRITICAL: Vehicle Theft Deterrent Relearn:
Upon installation, your vehicle’s anti-theft system must be synchronized with the new ECM. If the vehicle does not start, this procedure is required. It must be performed using a professional scan tool with access to GM’s TIS2Web programming service. Most professional repair shops can perform this service. -
Other Potential Relearns:
Depending on your vehicle’s specific condition and codes, additional procedures like a Crankshaft Position Variation Relearn or injector flow rate programming may be necessary.
Guaranteed Compatibility
This module, part number 12654088, is a direct replacement for service numbers 12654088 and 12653319. It is confirmed to fit the following vehicles equipped with the 6.6L Duramax diesel engine:
- 2013-2014 Chevrolet Silverado 2500 / 3500
- 2013-2014 GMC Sierra 2500 / 3500 (including Denali)
- 2013-2014 Chevrolet Express 2500 / 3500
- 2013-2014 GMC Savana 2500 / 3500
Note for 2014 Van Owners: Please verify your vehicle is ‘w/o pull-ahead design’ as specified in the fitment chart.