Restore Peak Performance to Your 2016 Express 3500 Van
Is your work van letting you down? If you’re dealing with a frustrating no-start condition, a persistent check engine light, or erratic engine behavior in your 2016 Express 3500, a failing Engine Control Module (ECM) is often the culprit. As the central computer of your vehicle, the ECM manages everything from fuel delivery and ignition timing to transmission shifting. When it fails, it can bring your operations to a grinding halt. This replacement ECM, part number 12663405, is the reliable, professional-grade solution to get your van back on the road and working as hard as you do.
We take the guesswork and hassle out of the repair. Unlike a generic module from a salvage yard, this unit comes fully programmed to your van’s specific Vehicle Identification Number (VIN). We load the latest, most stable software updates directly from GM, ensuring optimal performance, fuel efficiency, and compatibility. This means no expensive trips to the dealership for programming—it’s a direct-fit solution designed for both professional installers and capable DIYers.
A Technician’s Notebook: The Intermittent No-Start Nightmare
I once had a fleet manager bring in a 2016 Express 6.0L that was causing major headaches. The van would start and run perfectly for a week, then suddenly refuse to start for a day. The driver would get stranded, but by the time we got the van towed to the shop, it would fire right up. There were no hard codes, just a few stored U0100 (Lost Communication with ECM/PCM) faults. After checking all power and ground circuits to the ECM and finding them solid, we suspected an internal, heat-related failure in the module itself. We installed a VIN-programmed ECM just like this one. The intermittent no-start vanished, and the van has been a reliable part of their fleet ever since. These internal processor faults can be tricky to diagnose, but a quality replacement module is the definitive fix.
Is Your Vehicle Showing These Telltale Signs of ECM Failure?
- ✔ Check Engine Light is on with codes like P0601, P0606, or other internal processor faults.
- ✔ The engine cranks but will not start.
- ✔ Unexplained loss of engine power or poor fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Communication errors with your scan tool (e.g., U0100).
- ✔ Stalling for no apparent reason, either while driving or at idle.
- ✔ Misfires on multiple cylinders without a clear mechanical cause.
A Straightforward Guide to Installation
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- ✔ Locate the ECM: On the 2016 Express Van, the ECM is typically found in the engine compartment, on the left-hand (driver’s) side, often near the rear.
- ✔ Disconnect the Connectors: Carefully release the locking tabs on the wiring harness connectors and pull them straight out from the module. Inspect the connectors for any corrosion or damaged pins.
- ✔ Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the mounting hardware as you will need it for the new unit.
- ✔ Install the New ECM: Mount your new, pre-programmed ECM onto the bracket and secure it with the original hardware.
- ✔ Reconnect Everything: Firmly press the wiring harness connectors into the new module until they click into place. Reconnect the negative battery terminal.
- ✔ Perform Security Relearn: In most cases, you will need to perform a simple security relearn procedure. This typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating two more times. This allows the new ECM to sync with your vehicle’s anti-theft system. Afterwards, the vehicle should start and run correctly.
Guaranteed Fitment for Your GM Vehicle
This module is a direct replacement for part number 12663405 and also interchanges with part numbers 12668866, 12668994, 12643636, 12670335, 22819494, and 12692200. It is confirmed to fit a wide range of GM vehicles, including but not limited to:
- Chevrolet Express 2500/3500 Van (2016): With 4.8L or 6.0L engines.
- GMC Savana 2500/3500 Van (2016): With 4.8L or 6.0L engines.
- Chevrolet Silverado 2500/3500 (2012-2016): With 6.0L engine.
- GMC Sierra 2500/3500 & Denali (2012-2016): With 6.0L engine.
- Chevrolet Cruze (2012-2016)
- Chevrolet Sonic (2012-2016)
- Chevrolet Trax (2013-2016)
- Buick Encore (2013-2016)
- Chevrolet Volt (2011-2015)
- And more. Please verify your part number or contact us with your VIN to ensure compatibility.
Frequently Asked Questions
How does the programming process work?
It’s simple. After you complete your purchase, you will need to send us your vehicle’s 17-digit VIN. Our technicians will then use official GM equipment to flash the module with the correct software and the latest updates for your specific vehicle before we ship it to you.
Will I need to do anything else after installation?
After installing the module, you will need to perform a security relearn procedure, also known as a Passlock or anti-theft relearn. This is a simple key-on/key-off sequence that syncs the new ECM to your vehicle. Instructions are included, and it requires no special tools.
Is this a new or used part?
This is a high-quality, tested, and verified used OEM part that has been professionally prepared and programmed for your vehicle. It provides the same reliability and function as a much more expensive dealer part.
What if my original part number is different?
This module replaces several different GM part numbers. As long as your vehicle is on the compatibility list and you provide a valid VIN, we will ensure it is programmed correctly to function in your vehicle, even if the number on your old part is different from 12663405.
Do I need to send my old ECM back?
No core charge or return is required for this part. You can keep or dispose of your old module as you see fit.