Is your Chevrolet Express or GMC Savana van running rough, stalling, or showing a persistent check engine light? These are classic signs of a failing Engine Control Module (ECM), the central computer that manages your vehicle’s engine performance, fuel efficiency, and emissions. A faulty ECM can cripple your workhorse, leading to unpredictable behavior, poor fuel economy, and even a no-start condition that leaves you stranded. Don’t let a bad computer dictate your vehicle’s reliability.
This is a direct-fit replacement ECM, part number 12633238 (also compatible with 12633055), for a wide range of GM trucks and vans. The most critical service we provide is programming this module specifically to your vehicle’s Vehicle Identification Number (VIN). This ensures that all factory settings, security protocols (like the anti-theft system), and engine parameters are perfectly matched to your van’s original specifications. This eliminates the need for an expensive trip to the dealership for programming, making the installation process straightforward and saving you significant time and money.
From the Diagnostic Bay
We had a contractor come in with his 2012 Express 3500 work van. It was randomly stalling at stoplights and occasionally wouldn’t start in the morning. He’d already replaced the battery and alternator, but the intermittent electrical gremlins persisted. After hooking up our scanner, we saw erratic data from multiple sensors and communication loss codes pointing to the ECM. We installed one of our VIN-programmed modules, and the van fired up instantly and ran smoother than it had in years. He was back on the job site the same afternoon, a simple component swap having solved a problem that was costing him business.
Symptoms of a Failing GM Engine Computer
- ✔ Persistent Check Engine Light (CEL) illumination
- ✔ Engine stalling, stumbling, or misfiring
- ✔ Difficulty starting the engine or a complete no-start condition
- ✔ Noticeable decrease in fuel economy
- ✔ Poor acceleration and overall engine performance
- ✔ Transmission shifting issues or harsh shifts
- ✔ Communication error codes with diagnostic scan tools
Your Direct Solution: A Programmed 2010-2015 Express 3500 ECM
Replacing the ECM shouldn’t be a complicated ordeal. Our process is designed for both professional technicians and savvy DIYers. By providing us with your VIN during checkout, you receive a unit that is ready for installation right out of the box. We flash the module with the latest GM-certified software updates, which can often resolve underlying issues that were present even in the original factory programming. This ensures optimal performance and longevity. This module is the brain of your engine’s operation, and installing a correctly programmed unit is the key to restoring your vehicle’s factory performance and reliability.
Frequently Asked Questions
What is an ECM and what does it do?
The ECM, or Engine Control Module, is a powerful computer that acts as the ‘brain’ of your vehicle’s engine. It takes in data from sensors all over the engine and uses it to control critical functions like fuel injection timing, spark timing, and emissions systems to ensure the engine runs efficiently and cleanly.
Is this ECM ready to install when I receive it?
Yes! The key benefit of our service is that we program the ECM to your vehicle’s specific VIN before shipping it. This makes it a plug-and-play installation. In some cases, a security relearn procedure may be required, which is a simple process that can be done without special tools.
How do I provide my VIN for programming?
After you complete your purchase, you will need to send us your 17-digit VIN. You can typically add this in the notes section at checkout or reply to your order confirmation email. We cannot ship the part until we have your VIN to ensure correct programming.
What happens if I don’t replace a failing ECM?
Ignoring a failing ECM can lead to more severe problems. You may experience worsening fuel economy, engine damage from incorrect fuel/air mixtures, catalytic converter failure, and eventually, the vehicle may not start at all, leaving you stranded.
Will this fit vehicles other than the Express 3500?
Absolutely. This ECM, part number 12633238, has a very broad application across the GM lineup, including many Silverado, Sierra, Tahoe, Yukon, and even performance models like the Camaro and Corvette from this era. Please review the detailed fitment list on this page to confirm compatibility with your specific model and engine.