Restore Peak Performance to Your Workhorse Van
As a technician with over two decades of experience under the hood, I’ve seen firsthand how a failing Engine Control Module (ECM) can bring a reliable work van to a grinding halt. If your 2010-2014 Express 1500 is suffering from erratic behavior, poor fuel mileage, or a persistent Check Engine Light, you’re not just dealing with an annoyance—you’re losing time and money. This isn’t just a part; it’s the brain of your van’s 4.3L engine, and when it falters, everything from ignition timing to fuel delivery is compromised.
We offer a straightforward, dependable solution. This is a genuine GM Engine Control Module, service part number 12639471, that arrives at your door programmed specifically for your vehicle. Simply provide us with your Vehicle Identification Number (VIN) after your purchase, and we’ll flash the module with the very latest software updates from General Motors. This critical step ensures perfect communication between all your vehicle’s systems, restoring the smooth operation and reliability you depend on, without a costly trip to the dealership for programming.
Is Your Van Showing These Symptoms?
A faulty ECM can manifest in numerous ways, often mimicking other component failures. I’ve spent countless hours diagnosing these issues in the shop. Here are the most common signs that point directly to the module:
- ✔ Unexplained Check Engine Light illumination.
- ✔ Stalling, hesitation, or rough idling for no apparent reason.
- ✔ A noticeable drop in fuel economy.
- ✔ The engine cranks but refuses to start.
- ✔ Harsh or inconsistent automatic transmission shifting.
- ✔ Diagnostic Trouble Codes (DTCs) stored in memory, such as P0601 (Internal Control Module Memory Check Sum Error) or P0606 (ECM/PCM Processor Fault).
- ✔ Loss of communication with the scan tool.
Case Study: A Tricky Diagnosis
I remember a 2012 Savana 1500 from a local plumbing company that came into my bay with an intermittent no-start condition. The driver said it would be fine for days, then suddenly refuse to fire up. There were no consistent codes, just a general loss of communication fault that would appear and then clear itself. We checked grounds, wiring, and the fuel system—all were perfect. On a hunch, I tapped the ECM housing while my apprentice cranked the engine, and it fired right up. The problem was an internal fracture on the ECM’s circuit board. Swapping in a pre-programmed Express 1500 Van ECM like this one had the van back in service the same afternoon, saving the owner a hefty dealership bill and days of lost work.
A Straightforward Guide to Installation
Replacing your Express 1500 Van ECM is a task a confident DIYer can handle. In the Express and Savana vans, the module is conveniently located in the left-hand rear of the engine compartment. Follow these steps for a successful installation:
- Safety First: Disconnect the negative terminal from your vehicle’s battery and secure it away from the post to prevent any accidental reconnection.
- Locate the ECM: On your van, find the ECM mounted in the rear driver’s side of the engine bay.
- Disconnect Connectors: Carefully release the locking tabs on the electrical wiring harnesses and gently pull them straight out from the module. Never force them. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the mounting hardware that secures the old ECM to its bracket. Set the old module aside.
- Install the New Module: Mount your new, pre-programmed ECM in place and tighten the hardware.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new ECM until they click and lock into place. Reconnect the negative battery terminal.
- Perform Relearn Procedure: Turn the key to the ‘ON’ position (without starting) for 10 seconds, then ‘OFF’ for 10 seconds. Repeat this cycle three times. This helps the vehicle’s systems recognize the new module. Your van is now ready to start.
Will This Fit My Vehicle?
This engine control module is a direct-fit replacement for the following vehicles equipped with the 4.3L V6 engine. It is cross-compatible with service numbers 12635043, 12639471, and 12653246.
- ✔ 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 before we ship the part. We use your VIN to load the correct, updated GM software, so it’s ready for installation right out of the box.
What is the security or CASE relearn procedure?
After installation, you may need to perform a simple key-cycle relearn as described in the installation steps. In some cases, a Crankshaft Variation (CASE) relearn may be needed with a capable scan tool to clear a P1336 code, but the vehicle will run and drive without it.
Why do you need my VIN?
The Vehicle Identification Number (VIN) is essential. It allows us to access the specific software, calibrations, and security information for your exact vehicle build. This ensures perfect compatibility and function.
Is this a new or used part?
This is a high-quality, inspected, and tested original equipment (OE) component that has been professionally programmed for your vehicle.
Will this fix my transmission shifting problems?
In many cases, yes. The ECM works directly with the Transmission Control Module (TCM). If the ECM is sending bad data, it can cause poor shifting. Replacing a faulty ECM often resolves these related symptoms.