Is Your 2009 Sierra Running Rough? The ECM Might Be the Culprit.
The Engine Control Module (ECM), often called the engine computer, is the brain of your 2009 GMC Sierra 1500. It manages everything from fuel injection and ignition timing to transmission shift points and emissions controls. When it starts to fail, it can cause a cascade of frustrating and difficult-to-diagnose issues. You might be experiencing a persistent check engine light, poor fuel economy, stalling, or a complete no-start condition. Don’t let a faulty computer keep your powerful truck off the road. This is the direct, reliable solution you need.
This isn’t just a used part pulled from a salvage yard. This is a fully tested Engine Control Module, part number 12625455 (also compatible with 12629009), that is professionally programmed specifically for your truck. We use your vehicle’s unique Vehicle Identification Number (VIN) to load the latest, most stable GM factory software onto the module before it ships. This critical step ensures that the ECM communicates perfectly with your truck’s specific engine, transmission, and options package, restoring its original performance and reliability.
From the Diagnostic Bay
We had a 2009 Silverado (which uses the same ECM) come into the shop with a bizarre, intermittent misfire on cylinder 3 that only happened under light load. The owner had already replaced the spark plug, wire, coil, and even the fuel injector. Scopes showed the injector signal was dropping out randomly. After hours of tracing wires, we swapped in a known-good ECM. The problem vanished instantly. The driver circuit for that specific injector inside the original ECM was failing. A pre-programmed module like this one would have saved him hundreds in diagnostic labor and had him back on the road in under an hour.
Symptoms of a Failing 2009 Sierra 1500 ECM
- ✔ Persistent Check Engine Light (CEL) with various trouble codes.
- ✔ Engine stalling or shutting off unexpectedly while driving.
- ✔ Noticeable decrease in fuel mileage.
- ✔ Rough idling, engine misfires, or hesitation during acceleration.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Complete no-start condition where the engine cranks but won’t fire up.
- ✔ Communication errors with diagnostic scan tools.
The Plug-and-Play Advantage: No Dealer Visit Required
One of the biggest hurdles in replacing a modern vehicle’s computer is the need for expensive dealership programming. Our service completely eliminates that step. By flashing the module with your VIN, we handle the complex part for you. When you receive the part, installation is straightforward. In most cases, it’s a direct swap. You may need to perform a simple security relearn procedure (often called a CASE relearn), which can typically be done in your driveway without any special tools. This process syncs the new ECM with your vehicle’s anti-theft system. Instructions for this procedure are widely available online or in service manuals.
This ECM is a genuine OEM component, ensuring perfect fitment and function. It is compatible with a wide range of GM trucks, vans, and SUVs from the 2009-2010 model years, including the Silverado, Tahoe, Suburban, Escalade, and Express van. Please verify your original part number is 12625455 or 12629009 to ensure compatibility. By providing us with your VIN, you guarantee that you receive a module correctly configured for your vehicle’s powertrain and options.
Frequently Asked Questions
Do I need to have this ECM programmed by a dealer?
No. We program the module to your vehicle’s specific VIN before we ship it to you. This saves you the time, hassle, and expense of a trip to the dealership.
Is this part truly ‘plug and play’?
Yes, for the most part. Once installed, you may need to perform a simple security/anti-theft relearn procedure, which can usually be done without special tools. This syncs the new computer to your keys and vehicle.
What information do you need from me after I order?
After you place your order, you will need to provide us with your 17-digit Vehicle Identification Number (VIN). We cannot program and ship the module without it.
My original part number is 12629009. Will this work?
Yes, this module is a direct replacement for both 12625455 and 12629009. They are interchangeable part numbers for this application.
Where is the ECM located on my 2009 Sierra 1500?
On most 2009 Sierra and Silverado trucks, the ECM is located in the engine compartment on the driver’s side, near the front. It is a silver metal box with several large electrical connectors.