Get Your Duramax Back on the Job, Fast.
A failing Engine Control Module (ECM) in your heavy-duty GM truck isn’t just an inconvenience—it’s downtime that costs you time and money. When your workhorse is sidelined with starting issues, poor performance, or a persistent check engine light, you need a reliable solution, not a temporary fix. This is the definitive, pre-programmed ECM that gets your 6.6L Duramax-powered Silverado, Sierra, Express, or Savana running strong again. We take the guesswork out of the repair by flashing this module with the latest GM software updates, specifically matched to your truck’s VIN before it ever leaves our facility.
Common Symptoms & Your Solution
If your truck is experiencing any of the following, a faulty ECM is the likely culprit. This unit is the direct solution for issues such as:
- Complete no-start or intermittent starting problems
- Check engine light with communication-related diagnostic trouble codes (DTCs) like P0601, P0606, or U-codes
- Erratic transmission shifting or engine performance
- Fuel injector or other sensor circuits failing intermittently
- Inability for a scan tool to communicate with the engine computer
By installing our programmed 12658036 ECM, you’re not just replacing a part; you’re restoring the central nervous system of your truck’s powertrain, ensuring all components work in harmony as the factory intended.
Features & Benefits
- ✔ VIN-Programmed for Your Truck: Arrives flashed with the latest GM calibrations specific to your vehicle. No need for an expensive trip to the dealer for programming.
- ✔ Restored Engine Performance: Corrects engine stumbling, poor fuel economy, and hesitation caused by a faulty computer.
- ✔ Direct-Fit Replacement: Designed to replace original part numbers 12658036 and 12667377, guaranteeing a perfect fit in the factory location.
- ✔ Solve Stubborn Check Engine Lights: Provides a permanent fix for internal module faults that trigger persistent, hard-to-diagnose trouble codes.
- ✔ Peace of Mind: This unit is backed by our one-year replacement warranty.
An Expert’s Note on Installation: We’ve seen it all. A correctly programmed ECM is the foundation of a healthy powertrain. While the physical installation is straightforward, remember that your vehicle’s security system is designed to prevent theft. If the truck doesn’t start post-installation, a simple ‘Vehicle Theft Deterrent Relearn’ is required. This step syncs the new ECM with your truck’s anti-theft system. While this procedure is the responsibility of the installer and requires a proper GM diagnostic tool, handling the complex VIN-programming on our end saves you the most critical and costly step of the process. This attention to detail ensures our programmed 12658036 ECM is the most reliable solution to get you back to work.
Frequently Asked Questions
What information do I need to provide?
After you complete your purchase, you must provide us with your vehicle’s 17-digit Vehicle Identification Number (VIN). This is essential for us to program the ECM correctly for your specific truck.
Do I need to send you my old ECM?
No, there is no core charge or need to send us your old, failed part. This is a direct purchase of a replacement unit.
What is a ‘theft relearn’ and will I have to do it?
The Vehicle Theft Deterrent (VTD) system may prevent the truck from starting after the new ECM is installed. A ‘theft relearn’ procedure syncs the new computer to your vehicle’s security system. This is a standard procedure for this type of repair and is the responsibility of the installer. It requires a compatible high-level scan tool with GM software, such as tis2web.
Will this fix my specific problem?
This ECM will resolve any issues directly caused by an internal failure of the original engine computer. If your truck has symptoms like no-communication with the ECM or internal fault codes (e.g., P0606), this is the correct solution. It’s always recommended to have a professional diagnosis to confirm the ECM is the point of failure before ordering.
Is this part difficult to install?
The physical replacement is straightforward. The ECM is typically located in the engine compartment on the driver’s side. The main challenge for a DIY installer can be performing the necessary security and system relearns after installation. We recommend professional installation for a seamless repair.
Which vehicles does this programmed 12658036 ECM fit?
This module fits a range of 2014-2015 GM heavy-duty trucks and vans with the 6.6L Duramax diesel engine, including the Silverado 2500/3500, Sierra 2500/3500, and Express/Savana 2500/3500 vans. Please verify the part number to ensure exact fitment.