Description
2020 GMC Sierra 4.3L ECM / ECU – VIN Programmed | Plug & Play
This Engine Control Module (ECM / ECU) is a genuine OEM replacement for all 2020 GMC Sierra 4.3L models.
Each unit is VIN-programmed, updated, and fully tested for a true plug-and-play installation with no dealer visit required.
Built to OEM standards for reliability, calibration accuracy, and long-term performance.
Strict Testing & Quality Assurance
Every ECU is inspected, refreshed, and verified through advanced diagnostic tools. Testing includes:
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Complete communication & CAN-bus verification
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Sensor input/output and signal integrity checks
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Injector & ignition pulse simulation
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Power, ground, and load-circuit analysis
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Flash memory integrity and checksum validation
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Thermal and voltage-stress testing to confirm reliability
This ensures a fully functional, reliable, plug-and-play module you can install with confidence.
Important Note
Some vehicles equipped with IMMO (Immobilizer) or PATS (Passive Anti-Theft System) may require additional key programming after installation. This is normal for models where security data must be synchronized with the vehicle’s body control system.
For a 100% plug-and-play solution with no relearns, no key programming, and no compatibility issues, we recommend our ECU Cloning Service, which transfers all original security, immobilizer, and configuration data directly into the replacement unit.
Contact Us
Email: info@fixecm.com
Phone: Local: 647-247-8555 | Toll-Free: 1-800-915-5566





Carlos James –
I was really impressed with how straightforward the installation was—this ECM came already VIN programmed, so it truly was plug and play. Shipping was quick, and the unit fit perfectly with no glitches. After swapping it out, my Sierra fired right up and runs smoothly, just like new. Definitely a reliable choice if you want to get back on the road fast without any hassle.
Nathan Anderson –
Installed this ECM in minutes with zero hassle—exact fit and my truck runs like new again. Super fast delivery, highly recommend!
Noah Hall –
I was a bit nervous about ordering an ECM for my 2020 GMC Sierra, but this unit arrived quickly and was truly a plug-and-play replacement. The VIN was already programmed, so installation was smooth and hassle-free. I had it swapped out in just under an hour without needing any extra coding tools. Since the install, my truck runs flawlessly, and I haven’t experienced any error codes or hiccups. Definitely worth it if you want a no-fuss solution that gets you back on the road fast.