Restore Peak Performance to Your Workhorse Van
Is your 2010-2015 Express 3500 Van suddenly unreliable? If you’re dealing with frustrating no-start conditions, erratic engine behavior, or a dashboard full of warning lights, a failing Engine Control Module (ECM) is a very likely culprit. As the brain of your vehicle’s engine, a faulty ECM can bring your work to a grinding halt. This isn’t just an inconvenience; it’s lost time and money. This direct-fit ECM, part number 12633055, is the definitive 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 sourcing a module from a junkyard or a generic parts store, each unit we ship is meticulously programmed to your van’s specific Vehicle Identification Number (VIN). This means it arrives loaded with the latest GM factory software updates, ensuring optimal fuel efficiency, emissions compliance, and engine performance. This critical programming step eliminates the need for an expensive tow to the dealership and their costly programming fees, making this a smart, efficient fix for both professional mechanics and dedicated DIYers.
From the Diagnostic Bay: The Intermittent Stall Case
I once had a 2012 Express 3500 in my shop that was driving its owner, a plumber, crazy. The van would run perfectly for days, then suddenly stall at a stoplight and refuse to restart for 20 minutes. There were no consistent trouble codes, just a random U0100 (Lost Communication with ECM). After checking all the wiring and grounds, we hooked up a scope. We found that the 5-volt reference circuit, controlled by the ECM, would intermittently drop out when the module got hot. The internal processor was failing under thermal stress. Swapping in a properly programmed 2010-2015 Express 3500 ECM like this one solved the problem permanently. That van is still on the road, reliably getting to jobs every day.
Is Your Van’s ECM Failing?
A bad engine computer can cause a wide range of confusing symptoms. Here are the most common signs I’ve seen in my 20+ years of experience:
- ✔ Complete no-start or intermittent starting issues.
- ✔ Check Engine Light is on with communication codes (e.g., U0100, P0601, P0606).
- ✔ Poor or erratic automatic transmission shifting.
- ✔ Noticeable drop in fuel economy.
- ✔ Engine stalling, sputtering, or misfiring for no apparent reason.
- ✔ Other warning lights on, such as ABS or traction control, due to lost data.
A Straightforward Guide to Installation
Installing your new 2010-2015 Express 3500 ECM is a manageable job for a DIYer with basic tools. Because we program it beforehand, you skip the most complicated part of the process. Always follow proper safety procedures.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent accidental reconnection.
- Locate the ECM: On the Express and Savana vans, the ECM is typically located in the left-hand rear of the engine compartment, mounted to the inner fender or firewall.
- Disconnect the Connectors: Carefully release the locking tabs on the electrical harness connectors and pull them straight out from the module. Never force them. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. There are usually two or three bolts holding it in place.
- Install the New Module: Mount your new, pre-programmed ECM onto the bracket and secure it with the bolts.
- Reconnect Everything: Firmly plug the electrical connectors back into the new ECM until they click into place. Reconnect the negative battery terminal.
- Perform Security Relearn: You will need to perform a simple key-cycle security relearn procedure to sync the new ECM with your vehicle’s anti-theft system. This typically takes about 30 minutes and requires no special tools. Instructions are readily available online for your specific model.
Verified Vehicle Compatibility
This ECM is a direct replacement for part numbers 12633055 and 12633238. It is guaranteed to fit a wide range of GM vehicles. While the primary application is the 2010-2015 Express 3500 ECM, it also fits the following models. Please verify your part number before ordering.
- Chevrolet Express / GMC Savana Vans (1500, 2500, 3500): 2010-2015 with 4.8L, 5.3L, or 6.0L engines.
- Chevrolet Silverado / GMC Sierra (1500, 2500, 3500): 2010-2013 with 4.8L, 5.3L, 6.0L, or 6.2L engines.
- Cadillac Escalade (Base, ESV, EXT): 2010-2014.
- Chevrolet Tahoe / Suburban & GMC Yukon / Yukon XL: 2010-2014.
- Chevrolet Avalanche: 2010-2013.
- Chevrolet Camaro: 2010-2015 with 6.2L or 7.0L engines.
- Chevrolet Corvette: 2010-2013 with 6.2L or 7.0L engines.
- Chevrolet Caprice / SS: 2011-2017.
Frequently Asked Questions
How does the programming process work?
It’s simple. After you complete your purchase, you will need to provide us with your vehicle’s 17-digit VIN. Our technicians will use this VIN to access the latest official GM software for your exact vehicle configuration and flash it onto the ECM before it ships. This ensures it’s ready for installation upon arrival.
Do I need to do anything after installing it?
Yes. While the main engine programming is done, you will need to perform a security relearn procedure (also known as a Passlock or Passkey relearn). This syncs the new ECM to your vehicle’s anti-theft system and allows the engine to start. It’s a simple procedure that involves turning the key on and off in a specific sequence and takes about 30 minutes. No special scan tools are required.
Is this a new or used part?
This is a high-quality, tested, and verified used OEM part that has been inspected for full functionality. We then program it with fresh, updated software specific to your vehicle, essentially giving it a new operational life and resolving common factory software bugs.
Will this fix my specific problem?
This ECM will correct any issue directly caused by a faulty engine computer. If you have diagnosed the ECM as the point of failure (e.g., by confirming power/ground but no communication, or specific internal fault codes like P0601), then this part is the solution. It will not fix issues caused by other bad sensors or wiring problems.
What is the difference between part numbers 12633055 and 12633238?
These are interchangeable OEM part numbers from GM for the same hardware. Functionally, they are identical once programmed for a specific vehicle. Our module is a direct replacement for either number.