Get Your Workhorse Van Back on the Job with a Reliable ECM
As a technician with over two decades of experience, I know that vehicle downtime is more than an inconvenience—it’s lost revenue, especially for a dependable work vehicle like the 2016 Express 3500 Van. When the Engine Control Module (ECM), the electronic brain of your powertrain, starts to fail, it can create a cascade of frustrating and hard-to-diagnose problems. This isn’t just a part; it’s the central command for your engine’s performance, fuel efficiency, and emissions. We’re offering a dependable, direct-fit solution: a replacement ECM, part number 12668866, that is professionally programmed to your van’s specific Vehicle Identification Number (VIN) before it ships.
Case Study: A Tricky Diagnosis
I remember a 2016 Express 6.0L that came into my shop with a complaint of intermittent stalling at stoplights and a persistent Check Engine Light. The owner had already replaced the throttle body and a few sensors with no luck. A scan revealed a P0606 code (ECM Processor Fault), a classic sign of an internal computer failure. The module was intermittently failing under load. We installed a VIN-programmed ECM just like this one. The new module immediately resolved the communication errors, the stalling vanished, and the van ran smoothly. This highlights the importance of not just replacing the part, but ensuring it has the correct, stable software for your specific vehicle.
Is Your Van Exhibiting These ECM Failure Signs?
A failing ECM can manifest in numerous ways. If you’re experiencing any of the following, a faulty engine computer could be the culprit. I’ve seen these symptoms countless times in my bay.
- ✔ Check Engine Light is on with codes like P0601, P0606, or other processor faults.
- ✔ Unexplained loss of engine power or poor acceleration.
- ✔ Decreased fuel economy for no apparent reason.
- ✔ Engine cranks but refuses to start.
- ✔ Intermittent stalling or rough idling.
- ✔ Automatic transmission shifting erratically or harshly.
- ✔ Communication error codes (U-codes) indicating the ECM is not talking to other modules.
A Straightforward Guide to Installation
One of the biggest advantages of our service is that this 2016 Express 3500 Van ECM arrives ready for installation, saving you a costly trip to the dealership for programming. While professional installation is always recommended, a skilled DIYer can often perform this replacement.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow the system to fully discharge.
- Locate the ECM: On the 2016 Express Van, the ECM is typically found in the left-hand rear of the engine compartment. Consult your service manual to be certain.
- Disconnect and Remove: Carefully unplug the wiring harness connectors. They have locking tabs that must be released. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed ECM into place. Reconnect the wiring harnesses, ensuring they click securely into position.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Relearn Procedure: In many GM vehicles, a security relearn (also known as a Passlock or anti-theft relearn) may be required. This procedure typically involves turning the key to the ‘ON’ position for 10-15 minutes, then ‘OFF’, and repeating two more times before starting the engine. This allows the new ECM to sync with your vehicle’s anti-theft system.
Verified Fitment Across a Wide Range of GM Vehicles
This versatile Engine Control Module is a direct replacement for multiple part numbers and fits a broad selection of GM cars, trucks, and vans. Please verify your vehicle and original part number against this list. This module replaces part numbers: 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200.
ENCORE 13-16 (1.4L)
Cadillac:
ELR 14-16
Chevrolet:
CRUZE 12-16 (Gasoline)
EXPRESS 2500/3500 VAN 16 (4.8L, 6.0L)
SILVERADO 2500/3500 PICKUP 12-16 (6.0L)
SONIC 12-16 (1.4L)
SPARK 14-15 (Gasoline)
SUBURBAN 3500 16
TRAX 13-16
VOLT 11-15
GMC:
SAVANA 2500/3500 VAN 16 (4.8L, 6.0L)
SIERRA 2500/3500 PICKUP 12-16 (6.0L)
SIERRA DENALI 2500/3500 12-16 (6.0L)
Why do you need my VIN?
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. We use it to load the exact, correct GM-certified software for your vehicle’s specific configuration, including engine, transmission, and emissions options. This ensures your new 2016 Express 3500 Van ECM functions perfectly right out of the box.
Is this part truly plug-and-play?
Yes, for the most part. Because we pre-program the module, you will not need a GM dealership scan tool for software installation. However, as mentioned in the installation guide, a simple key-cycle security relearn procedure is often necessary to sync the module with your vehicle’s anti-theft system.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the original ECM (e.g., codes P0601-P0606), then this replacement module will resolve the issue. However, if the light is on due to a faulty sensor or another component, you will still need to diagnose and repair that separate problem.
What if my original part number is slightly different?
This module is a direct replacement for several part numbers, including 12668994, 12643636, and others listed in the fitment section. GM often supersedes part numbers. As long as your vehicle is listed and your original part number is in our cross-reference list, this module will work perfectly.