Is Your Work Van Letting You Down?
A failing Engine Control Module (ECM) in your 2016 Chevy Express 3500 isn’t just an inconvenienceโit’s a threat to your livelihood. When the brain of your engine starts to malfunction, you’ll notice frustrating and costly symptoms: a persistent Check Engine Light, rough idling, sudden stalling, poor fuel economy, or even a complete no-start condition. These issues can sideline your vehicle and disrupt your business. You need a reliable, straightforward solution that gets you back on the road without the dealership hassle and expense.
The Direct-Fit, Programmed Solution
This is a genuine GM Engine Control Module, part number 12670335, that arrives at your door ready for installation. The critical difference is our professional programming service. Before we ship, we flash the module with the latest GM-certified software, specifically matched to your vehicle’s VIN. This means no expensive trips to the dealer for programming. It’s designed to restore your van’s original performance, efficiency, and reliability right out of the box.
Real-World Diagnostics: More Than Just a Part
“A customer’s 2016 Express 3500 came into my shop last month with what he swore was a failing transmission. It was shifting hard and erratically, especially between 2nd and 3rd gear. He had already spent money on a transmission fluid service elsewhere with no improvement. After hooking up my pro-level scan tool, I noticed erratic data PIDs from the throttle position sensor and torque converter clutch solenoid, but the components themselves tested fine. The real culprit? The ECM. It was sending faulty signals, causing the transmission to behave poorly. A new, properly programmed ECM fixed the ‘transmission’ problem instantly. It’s a classic case I’ve seen dozens of times where the ECM is the root cause of what seems like a completely different issue.”
Is Your Vehicle Showing These Symptoms?
A faulty ECM can manifest in numerous ways. If you’re experiencing any of the following, this module is the likely solution:
- โ Persistent Check Engine Light (CEL) with various engine or communication codes.
- โ Unexplained drop in fuel mileage.
- โ Engine stalling, stumbling, or hesitating during acceleration.
- โ Rough or inconsistent idle.
- โ Hard starting or no-start conditions.
- โ Seeming transmission shifting problems.
- โ Failure to pass an emissions test.
Simple, Plug-and-Play Installation Guide
You don’t need to be a master technician to replace this module. With basic tools, you can have your van running properly in under an hour.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post.
- Locate the ECM: On the 2016 Express 3500, the ECM is typically found in the left-hand (driver’s side) rear of the engine compartment.
- Disconnect Connectors: Carefully release the locking tabs on the electrical wiring harnesses and pull them straight out from the module. Do not force them. Inspect the connectors for any corrosion or bent pins.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed ECM securely onto the bracket.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect your battery terminal.
- Final Steps: Start the engine. The check engine light may be on initially. In most cases, a short drive cycle (10-15 minutes of mixed city/highway driving) will allow the vehicle’s systems to relearn and the light will turn off.
Guaranteed Compatibility
This module is a direct replacement for a wide range of GM vehicles and part numbers. Simply provide your VIN at checkout to ensure perfect programming. This part interchanges with the following numbers:
12668866, 12668994, 12643636, 12663405, 12670335, 22819494, 12692200
This module fits a vast array of vehicles including various Chevrolet Cruze, Sonic, Trax, Volt, Spark, Silverado, Suburban, and Express models, as well as GMC Sierra, Savana, and Buick Encore models. Please use the fitment chart to confirm compatibility with your specific vehicle and options.