Restore Peak Performance to Your GM Vehicle
Is your work van or truck suddenly running rough, refusing to start, or flashing a persistent Check Engine Light? As the central computer for your engine, a failing Engine Control Module (ECM) can cause a host of frustrating and costly problems. I’ve seen it countless times in my 20+ years in the shop: what seems like a major mechanical failure is often just a faulty ECM. This isn’t just a replacement part; it’s a reliable, long-term solution designed to get your vehicle back to factory-spec operation without the dealership price tag or hassle.
A Technician’s Notebook: The Intermittent No-Start Nightmare
A local contractor brought in his 2016 Express 2500 work van with a problem that was costing him money every day. It would start fine for a week, then suddenly refuse to crank for an hour. No codes, no warning. After checking the battery, starter, and ignition system—all of which tested fine—we hooked up a high-end scanner to monitor live data. We noticed the ECM would occasionally lose communication with other modules right before the no-start event (a classic U0100 symptom). This pointed to an internal failure in the module, likely from years of heat cycles and vibration. We replaced it with a VIN-programmed unit like this one, and the van has been starting reliably ever since. It’s a textbook example of how a failing ECM can mimic other, more expensive problems.
The Critical Importance of VIN Programming
Don’t make the mistake of buying a used ECM from a junkyard and hoping it works. Modern vehicles require the ECM to be programmed specifically to your vehicle’s Vehicle Identification Number (VIN). This process ensures all systems—from the fuel injectors and ignition timing to the transmission and anti-theft system—communicate correctly. We handle this critical step for you. Simply provide your VIN during checkout, and our technicians will flash this module with the latest, most stable GM-approved software for your exact vehicle. This not only guarantees compatibility but can also resolve underlying drivability issues that were present even with your old module.
Is Your Vehicle Showing These Failure Signs?
- ✔ Check Engine Light is on with codes like P0601 (Internal Control Module Memory Check Sum Error), P0606 (ECM/PCM Processor Fault), or U0100 (Lost Communication With ECM/PCM).
- ✔ Engine cranks but refuses to start.
- ✔ Intermittent stalling or rough idling.
- ✔ Noticeable decrease in fuel economy.
- ✔ Hesitation or stumbling during acceleration.
- ✔ Failure to pass an emissions test.
- ✔ Transmission shifting issues or erratic behavior.
A Straightforward Guide to Installation
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow capacitors to discharge.
- ✔ Locate the Module: On the 2016 Express 2500 Van, the ECM is typically found in the engine compartment on the driver’s side, near the firewall or inner fender.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. They have locking tabs that need to be released. Once unplugged, unbolt the old ECM from its mounting bracket.
- ✔ Install the New Module: Mount the new, pre-programmed ECM in the same location and securely fasten the bolts. Reconnect the electrical harnesses, ensuring they click firmly into place.
- ✔ Reconnect Power: Reattach the negative battery terminal.
- ✔ Final Steps: In some cases, a security relearn procedure may be necessary, which can typically be done without special tools by cycling the key. Your vehicle is now ready to start.
Verified Vehicle Compatibility
This module, part number 12668991, is a direct replacement for a wide range of GM vehicles and interchanges with part numbers 12668866, 12668994, 12643636, 12663405, 12670335, 22819494, and 12692200. It is guaranteed to fit the following models, among others:
- ✔ 2016 Chevrolet Express 2500 / 3500 Van (4.8L, 6.0L)
- ✔ 2016 GMC Savana 2500 / 3500 Van (4.8L, 6.0L)
- ✔ 2012-2016 Chevrolet Silverado 2500 / 3500 Pickup (6.0L)
- ✔ 2012-2016 GMC Sierra 2500 / 3500 Pickup (6.0L)
- ✔ 2011-2015 Chevrolet Volt
- ✔ 2012-2016 Chevrolet Sonic (1.4L)
- ✔ 2012-2016 Chevrolet Cruze
- ✔ 2013-2016 Buick Encore (1.4L)
- ✔ 2013-2016 Chevrolet Trax
- ✔ 2014-2016 Cadillac ELR
- ✔ 2014-2015 Chevrolet Spark
- ✔ 2016 Chevrolet Suburban 3500
Frequently Asked Questions
Do I need to do anything after I install it?
No. This module comes pre-programmed to your VIN. In most cases, it is a plug-and-play installation. Some vehicles may require a simple key-cycle security relearn, but no expensive scan tools are needed.
How do I provide my VIN?
After you complete your purchase, you will receive instructions on how to send us your vehicle’s 17-digit VIN. We cannot ship the module until we receive this information.
Is this a new or used part?
This is a high-quality, inspected, and tested replacement part that has been programmed with the latest GM software, ensuring reliability and proper function.
Will this fix my car’s specific problem?
This module will correct issues directly caused by a faulty ECM. While the symptoms listed are common indicators of ECM failure, we always recommend a proper diagnosis by a qualified mechanic to confirm the ECM is the root cause before purchasing.
What if I have a different part number on my old module?
This module replaces several part numbers, including 12668866, 12668994, and 12643636. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.