Restore Peak Performance to Your GM Workhorse
Is your 2010-2014 Express 1500 Van running rough, stalling unexpectedly, or showing a persistent Check Engine Light? These are classic signs of a failing Engine Control Module (ECM), the computer that acts as your vehicle’s brain. A faulty ECM can cause a cascade of frustrating issues, from poor fuel mileage to a no-start condition, directly impacting your work or daily life. In my 20+ years of experience, I’ve seen how a bad ECM can mimic a dozen other problems, leading to wasted time and money on incorrect repairs. This module is the definitive solution.
We take the guesswork and hassle out of the repair. This genuine GM ECM, compatible with service number 12635043, arrives at your door fully programmed to your vehicle’s specific Vehicle Identification Number (VIN). We load the latest, most stable software updates from GM, ensuring optimal engine performance, fuel efficiency, and emissions control. This means no expensive trips to the dealership for programming—a savings of both time and money. For any professional mechanic or dedicated DIYer, getting a pre-programmed Express 1500 Van ECM is the most efficient way to get the job done right the first time.
From the Diagnostic Bay
I remember a 2012 Express work van that came into the shop with an intermittent no-start condition. The owner, a local plumber, was losing business every day it was down. His previous mechanic had already replaced the fuel pump and crank sensor, but the problem persisted. The scanner showed a P0606 code (ECM/PCM Processor Fault) that would only appear when the engine was hot. After confirming the wiring and grounds were solid, we knew the ECM was internally failing under heat soak. We sourced a VIN-programmed module just like this one. The installation took less than an hour, and the van fired up perfectly, hot or cold. The owner was back on the road the same day, a testament to how a direct-fit, correctly programmed part is the key to a fast and accurate repair.
Is Your Van Exhibiting These ECM Failure Signs?
A failing ECM can manifest in various ways. If you’re experiencing any of the following, it’s a strong indicator that your engine’s computer needs attention:
- ✔ Persistent Check Engine Light (CEL)
- ✔ Engine stalling, stumbling, or misfiring
- ✔ Vehicle won’t start or is difficult to start
- ✔ Noticeable decrease in fuel economy
- ✔ Poor or erratic automatic transmission shifting
- ✔ Communication error codes, such as U0100 (Lost Communication With ECM/PCM)
- ✔ Internal module failure codes, like P0601 or P0606
A Straightforward Guide to Installation
Installing your new Express 1500 Van ECM is a manageable task for a confident DIYer. On these vans, the module is located in the left-hand rear of the engine compartment. Always follow proper safety procedures.
- Safety First: Disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes for the system capacitors to discharge.
- Locate the ECM: Find the module in the LH rear of the engine bay. It will have several large electrical connectors attached to it.
- Disconnect Connectors: Carefully release the locking tabs on each electrical harness connector and pull them straight out from the module. Never force them. Inspect the connectors for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the hardware, as you may need it for the new module.
- Install the New Module: Mount your new, pre-programmed ECM securely onto the bracket.
- Reconnect and Secure: Plug the electrical connectors firmly into the new module until they click into place. Ensure the locking tabs are fully engaged.
- Final Step: Reconnect the negative battery terminal. Your vehicle is now ready to start. In some cases, a security relearn procedure may be required, which can typically be done without special tools by cycling the key.
Verified Vehicle Compatibility
This module is a direct-fit replacement for the following vehicles equipped with the 4.3L V6 engine. It is compatible with ECM service numbers 12635043, 12639471, and 12653246. Please provide your VIN upon purchase to ensure perfect programming.
- 2010-2014 Chevrolet Express 1500 Van (4.3L)
- 2010-2014 GMC Savana 1500 Van (4.3L)
- 2010-2013 Chevrolet Silverado 1500 Pickup (4.3L)
- 2010-2013 GMC Sierra 1500 Pickup (4.3L)
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle all the programming for you before shipment. We use your VIN to load the latest GM software, so it’s ready for installation right out of the box.
Where 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 part until we receive this information.
Is this a difficult part to install?
For someone with basic mechanical skills, this is a straightforward replacement. It involves disconnecting the battery, unplugging connectors, and unbolting the old module. No special tools are typically required.
Will this fix my Check Engine Light?
If the Check Engine Light is caused by an internal failure of the ECM (e.g., codes P0601, P0606, U0100), then this part is the correct fix. It’s crucial to properly diagnose the issue before ordering.
What if my original part number is different?
This module replaces multiple service numbers, including 12635043, 12639471, and 12653246. As long as your vehicle is on the compatibility list, this module will function correctly once programmed to your VIN.