Is your 2010-2014 Express 1500 Van giving you headaches? If you’re dealing with a persistent check engine light, rough idling, stalling, or a frustrating no-start condition, the problem often points directly to a failing Engine Control Module (ECM). As the brain of your vehicle’s engine, a faulty ECM can disrupt everything from fuel delivery to spark timing, making your reliable workhorse feel unpredictable. Don’t let a bad module keep your van off the road and costing you money.
This is a direct-fit replacement ECM, service part number 12653246, that solves these common issues. The best part? We handle the most complicated step for you. Before we ship it, we will program the module with the very latest GM-certified software updates, specifically matched to your van’s Vehicle Identification Number (VIN). This means no expensive trips to the dealership for programming. It arrives at your door ready for a straightforward installation, getting you back to work faster.
A Technician’s Notebook
I remember a call from a local plumbing company. Their 2012 Express 1500 with the 4.3L V6 would randomly refuse to start, but only after it had been running for a while. They had already replaced the battery and checked the starter. When I hooked up my scan tool, I found no communication with the ECM and a tell-tale DTC P0601 (Internal Control Module Memory Check Sum Error). Heat soak was causing an internal failure in the module’s processor. Instead of having them tow the van to a dealer, we ordered a VIN-programmed ECM. The next day, it took me less than 30 minutes to swap it in their parking lot. The van fired right up, and they haven’t had an issue since. This pre-programmed solution saved them a tow bill and a full day of lost revenue.
Is Your Van Showing These Symptoms?
A failing ECM can manifest in many ways. Over my 20+ years in the bay, these are the most common signs I’ve seen with this specific GM platform. If you’re experiencing several of these, your ECM is the likely culprit.
- ✔ Check Engine Light: Often the first warning. Common codes include P0601, P0602, P0606, or other communication-related faults (U-codes).
- ✔ Engine Stalling or Misfiring: The engine may cut out unexpectedly while driving or run rough, feeling like it’s about to stall.
- ✔ No-Start Condition: You turn the key, the engine cranks, but it refuses to start due to a lack of fuel or spark command from the ECM.
- ✔ Poor Fuel Economy: A sudden and unexplained drop in your van’s MPG can be caused by incorrect fuel mixture calculations from a faulty module.
- ✔ Reduced Engine Power: The vehicle may feel sluggish or go into a “limp mode” to protect the engine.
- ✔ Communication Issues: Your scan tool may be unable to connect to the engine control module.
A Straightforward Guide to Installation
Installing your pre-programmed 2010-2014 Express 1500 ECM is a job most DIYers or any professional mechanic can handle with basic tools. The module is located in the left-hand rear of the engine compartment.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait at least 10 minutes to allow all system capacitors to discharge.
- Locate the ECM: On the Express and Savana vans, find the ECM mounted in the LH rear of the engine bay.
- Disconnect Connectors: Carefully release the locking tabs on the electrical wiring harnesses and pull them straight out from the module. Avoid pulling on the wires themselves.
- Remove the Old Module: Unbolt the mounting hardware holding the old ECM in place and remove it from the vehicle.
- Install the New ECM: Mount your new, pre-programmed ECM in the same location and secure it with the original hardware.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new module until they click into place. Reconnect the negative battery terminal.
- Security Relearn: In some cases, a simple security relearn procedure may be required. This can typically be done without special tools by cycling the key. Turn the key to ‘ON’ for 10 minutes, ‘OFF’ for 10 seconds, and repeat two more times. The vehicle should then start.
Guaranteed Vehicle Compatibility
This module is a direct replacement for service numbers 12635043, 12639471, and 12653246. It is guaranteed to fit the following vehicles equipped with the 4.3L V6 engine:
- ✔ 2010-2014 Chevrolet Express 1500 Van (Electronic Control Module; LH rear engine compartment)
- ✔ 2010-2014 GMC Savana 1500 Van (Electronic Control Module; LH rear engine compartment)
- ✔ 2010-2013 Chevrolet Silverado 1500 Pickup (Electronic Control Module; LH front under battery)
- ✔ 2010-2013 GMC Sierra 1500 Pickup (Electronic Control Module; LH front under battery)
Our programming service ensures this 2010-2014 Express 1500 ECM functions perfectly with your van’s specific systems, restoring its original performance and reliability.
Frequently Asked Questions
How do I provide my VIN number?
After you complete your purchase, you will receive an email with instructions. Simply reply to that email with your vehicle’s 17-digit VIN, or include it in the ‘Notes to Seller’ section during checkout. We cannot program or ship the module without it.
Is this ECM truly plug-and-play?
Yes. Because we program it to your specific VIN before shipping, it is ready for installation right out of the box. In some instances, a simple key-cycle security relearn (as outlined in the installation guide) is needed, but no expensive scan tools are required.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the ECM (like codes P0601, P0606, etc.), then yes, this part will resolve the issue. It’s crucial to properly diagnose the problem first, as the light can be triggered by other failing sensors or components.
What if I have a different service number on my old part?
This module is a compatible replacement for service numbers 12635043, 12639471, and 12653246. As long as your vehicle is listed in our compatibility chart, this part will work correctly once programmed to your VIN.
Do I need to return my old ECM?
No core charge or return is required for this part. You can keep or responsibly dispose of your old module.