Is Your Buick Lucerne Running Rough? The ECM Might Be the Culprit.
If your 2009, 2010, or 2011 Buick Lucerne is experiencing perplexing issues like stalling, poor fuel economy, a persistent Check Engine Light, or even a complete no-start condition, the problem may lie with its most critical component: the Engine Control Module (ECM). The ECM is the central computer of your vehicle, responsible for managing everything from fuel injection and ignition timing to transmission shifting and emissions control. When it fails, it can create a cascade of problems that are often difficult to diagnose.
A failing ECM doesn’t just affect performance; it can leave you stranded. Symptoms often start subtly—a slight hesitation, an occasional rough idle—but can escalate quickly. You might notice your transmission shifting erratically or the engine misfiring under load. These are not just annoyances; they are clear signals that the brain of your engine is in distress. Ignoring these signs can lead to more significant and costly damage to other components, such as the catalytic converter.
Diagnosing and Replacing Your 2009-2011 Lucerne Engine Module
This genuine GM Engine Control Module, part number 12630464, is the definitive solution for restoring your vehicle’s performance and reliability. Unlike generic modules that require expensive trips to the dealership for programming, this unit comes fully programmed to your specific vehicle. We use your Vehicle Identification Number (VIN) to load the latest, most stable software updates directly from GM. This ensures perfect compatibility and seamless integration with your Lucerne’s existing systems, right out of the box. The process is simple: you provide your VIN during checkout, and we handle the complex programming before the part ever leaves our facility. This saves you hundreds of dollars in dealer fees and hours of vehicle downtime.
From the Diagnostic Bay
We had a 2010 Lucerne with the 4.6L V8 come into the shop with a complaint of intermittent stalling and a whole host of seemingly unrelated trouble codes—U-codes for lost communication, P-codes for sensor circuits, and even a transmission code. The owner had already replaced the alternator and battery. We checked all the main power and ground connections to the ECM, which were solid. After hooking up a scope, we could see the 5-volt reference signal dropping out randomly, causing the sensors to go offline and the engine to quit. This pointed directly to an internal failure in the original ECM. We installed one of our pre-programmed modules, performed the security relearn, and the car ran perfectly. It’s a classic case where chasing individual codes would have been a waste of time and money; the core problem was the central computer itself.
Common Symptoms of a Failing ECM
- ✔ Check Engine Light: The most common indicator, often with codes related to processor failure (e.g., P0606) or communication errors.
- ✔ Engine Stalling or Misfiring: The engine may stall unexpectedly while driving or at idle, and you may experience random misfires.
- ✔ No-Start Condition: The engine cranks but refuses to start due to a lack of spark or fuel injector pulse commands from the ECM.
- ✔ Poor Fuel Economy: Incorrect fuel mixture calculations can cause a sudden and significant drop in MPG.
- ✔ Erratic Transmission Shifting: The ECM communicates with the Transmission Control Module (TCM), and a failure can lead to harsh or incorrect gear changes.
- ✔ Performance Issues: Noticeable loss of power, hesitation on acceleration, and a generally sluggish feel.
- ✔ Cooling Fans Not Working: The ECM controls the cooling fans, and a failure can cause the engine to overheat.
This module is a direct replacement for a wide range of GM vehicles, not just the Buick Lucerne. It is interchangeable with numerous service numbers, including 12636659, 12639300, 12628993, and more, ensuring broad compatibility. By purchasing this pre-programmed unit, you are not just buying a part; you are buying a complete, ready-to-install solution that restores your vehicle to its factory specifications.
Frequently Asked Questions
Do I need to get this ECM programmed by a dealer?
No. The main benefit of our service is that we program the module for you before shipping. Simply provide your vehicle’s 17-digit VIN when you place your order, and it will arrive ready for installation.
Where is the ECM located on my 2009-2011 Buick Lucerne?
On the 2009-2011 Buick Lucerne with the 4.6L V8 engine, the Engine Control Module is typically located in the lower part of the air cleaner box assembly in the engine bay.
What happens after I install the new module?
After installation, you will likely need to perform a security relearn procedure, also known as a Passlock or anti-theft relearn. This procedure can usually be done without special tools and involves a sequence of key turns. Instructions are widely available online or in service manuals.
Is this part compatible with other vehicles besides the Lucerne?
Yes, this ECM is compatible with a wide variety of GM vehicles from that era, including the Cadillac DTS, Chevy Colorado, GMC Canyon, Hummer H3, and more. Please check the detailed fitment list on this page to confirm compatibility with your specific model and engine.
What if I don’t provide my VIN?
We cannot ship the module without your VIN. The programming is essential for the part to function correctly in your vehicle. Your order will be placed on hold until we receive the VIN from you.