Is Your 6.6L Duramax Running Rough? Get a Reliable, Programmed Solution.
If you’re dealing with a persistent check engine light, erratic engine behavior, or a no-start condition in your 2013-2014 GM HD truck, a failing Engine Control Module (ECM) is a very likely culprit. As the central computer for your powertrain, even a minor internal fault can cause major headaches. This isn’t just a replacement part; it’s a direct, VIN-programmed solution designed to get your truck back to factory-spec performance without the high cost and hassle of a dealership visit for programming.
This is a fully tested, used OEM Engine Control Module, service part number 12653319 (also interchangeable with 12654088). Before we ship it, our technicians will flash the module with the latest official GM software calibrated specifically to your truck’s Vehicle Identification Number (VIN). This critical step ensures all systems communicate correctly right out of the box.
Common Symptoms of a Failing 2013-2014 Sierra 2500 ECM:
- โ Persistent Check Engine Light (CEL) with communication-related fault codes.
- โ Vehicle randomly enters ‘limp mode’ or reduced power mode.
- โ Unexplained stalling or difficulty starting the engine.
- โ Poor fuel economy and noticeable loss of power.
- โ Communication issues with diagnostic scan tools.
- โ Harsh or incorrect transmission shifting patterns.
Expert Pro Tip: Don’t Skip the CASE Relearn!
After installing a new ECM on these 6.6L Duramax engines, performing the Crankshaft Position System Variation Learning Procedure (often called a CASE relearn) is absolutely critical. I’ve seen dozens of trucks in my shop that ran rough or had a persistent P0300-range misfire code after an ECM swap simply because this step was missed. It requires a professional scan tool, but it synchronizes the new ECM with the precise position of your engine’s crankshaft, ensuring accurate timing and smooth operation. Skipping it can lead to a frustrating diagnostic chase that points back to the module you just replaced.
Installation & Required Procedures
Physically swapping the module is straightforward, but post-installation steps are required for proper vehicle operation. You or your mechanic will need access to a professional-grade scan tool with GM software capabilities (like TIS2Web).
- Safety First: Disconnect the negative battery terminal and wait 15 minutes for all systems to discharge.
- Locate the ECM: On Sierra and Silverado pickups, the ECM is located in the front left (driver’s side) of the engine compartment. On Express and Savana vans, it’s in the left rear of the engine compartment.
- Disconnect Connectors: Carefully release the locking tabs and unplug the wiring harnesses from the old module. Inspect the connectors for any corrosion or bent pins.
- Swap Modules: Unbolt the old ECM and install the new one in its place.
- Reconnect: Securely plug the wiring harnesses into the new module and reconnect the battery terminal.
IMPORTANT: Post-Installation Relearn Procedures
This module is programmed to your VIN, but for security and performance, your vehicle requires these final steps. It is the buyer’s responsibility to ensure these are completed.
- Vehicle Theft Deterrent System (VTDS) Relearn: If the truck does not start after installation, the security system must be synchronized to the new ECM. This is a mandatory step.
- Crankshaft Variation (CASE) Relearn: As mentioned in our pro tip, this is essential for engine timing and performance.
- Injector Flow Rate Programming: Your specific injector flow rate values may need to be entered into the new ECM for optimal fuel delivery.
Guaranteed Fitment for 6.6L Duramax Engines
This module is a direct replacement for the following vehicles equipped with the 6.6L 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 Vans: Fits models without the ‘pull-ahead design’ option. Please verify compatibility.