Restore Peak Performance to Your 6.6L Duramax Engine
Is your dependable Silverado, Sierra, or Express van suddenly plagued with frustrating issues? A no-start condition, erratic transmission shifting, a persistent Check Engine Light, or a complete loss of communication with your scan tool are all classic signs of a failing Engine Control Module (ECM). As the central computer for your powertrain, when the ECM falters, it can bring your entire vehicle to a standstill. Don’t let a faulty module sideline your workhorse. This genuine, used OEM ECM is the reliable and cost-effective solution to get you back on the road with confidence.
The Smart Solution: A VIN-Programmed 2013-2014 Silverado 3500 ECM
Forget the hassle and high cost of a dealership visit for programming. We take care of the critical first step for you. Before this module ever leaves our facility, our technicians will program it using your vehicle’s unique VIN. This process loads the latest, most stable factory software and calibrations directly from GM, ensuring the ECM is perfectly matched to your truck’s specific configuration. This is the same procedure a dealer would perform, but done for you ahead of time for a smoother installation process.
Is Your ECM Failing? Watch for These Symptoms:
- โ Complete no-start or intermittent starting problems
- โ Check Engine Light is on with various communication (U-prefix) or processor fault codes
- โ Poor fuel economy and reduced engine power
- โ Harsh or incorrect automatic transmission shifting
- โ Scan tool cannot communicate with the engine computer
Expert Pro Tip: Don’t Forget Injector Flow Rates!
I’ve seen it countless times in the shop: a customer replaces a Duramax ECM but the engine still runs rough. Why? They forgot to program the new module with the Injector Quantity Adjustment (IQA) numbers. Each injector has a unique flow rate number printed on its body. After installing this ECM, it’s critical that you or your mechanic use a capable scan tool to enter the IQA numbers from your truck’s original injectors into this replacement module. Skipping this step will lead to poor performance, smoke, and potential long-term engine issues.
Installation & Required Setup Procedures
Physically swapping the ECM is straightforward, but for the vehicle to operate correctly, a few final steps are required by the installer. This is standard procedure for any ECM replacement on these GM vehicles.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the ECM: On Silverado and Sierra pickups, it’s on the driver’s side of the engine compartment. On Express and Savana vans, it’s in the LH rear of the engine compartment.
- Disconnect & Remove: Carefully unplug the electrical connectors and unbolt the old module.
- Install New ECM: Mount the replacement ECM and securely reconnect all electrical harnesses. Ensure they click into place.
- Reconnect Battery: Reattach the negative battery terminal.
IMPORTANT: Post-Installation Requirements
Once the ECM is installed, the vehicle’s security system needs to recognize it. If the truck does not start, you MUST perform the Vehicle Theft Deterrent (VTD) relearn using a professional tool with access to GM’s TIS2Web service. Additionally, other system initializations, such as the Crankshaft Variation Relearn and the Injector Flow Rate programming mentioned in our tip, will need to be completed by the end-user or their mechanic to ensure proper engine function.
Guaranteed Fitment & Part Number Information
This ECM, part number 12654088, is a direct replacement for service numbers 12654088 and 12653319. Please verify the number on your original module to ensure a perfect match. This part is a confirmed fit for 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 Van
- 2013-2014 GMC Savana 2500 / 3500 Van