If your 2009-2011 Buick Lucerne is giving you headaches with unpredictable stalling, a persistent Check Engine Light, or a frustrating no-start condition, the root cause is often the very brain of your engine: the Engine Control Module (ECM). As a technician with over two decades of experience, I’ve seen firsthand how a failing ECM can mimic a dozen other problems, leading to wasted time and money on parts you don’t need. This isn’t just a component; it’s the central command for your vehicle’s performance and efficiency.
We’re offering a direct-fit, reliable solution. This ECM, part number 12630464, is not just a replacement part. It arrives at your door fully programmed with the latest official GM software updates, specifically matched to your vehicle using its VIN. This critical step eliminates the need for an expensive trip to the dealership and ensures your Lucerne operates exactly as the manufacturer intended. By restoring proper communication between sensors and systems, this module can bring back the smooth, reliable performance you’ve been missing.
Signs Your Lucerne’s ECM Is Failing
A faulty ECM can cause a wide range of confusing symptoms. If you’re experiencing any of the following, there’s a strong possibility your engine’s computer is the culprit. In my shop, these are the classic red flags I look for:
- âś” Unexplained stalling or engine shutting off while driving
- âś” Intermittent or total no-start conditions
- âś” Poor fuel economy and reduced engine power
- âś” Harsh or erratic automatic transmission shifting
- âś” Check Engine Light is on with internal module codes like P0601, P0602, or P0606
- âś” Communication loss codes, such as U0100, indicating the ECM isn’t talking to other modules
- âś” Misfire codes that persist even after replacing spark plugs and coils
A Technician’s Notebook: The Phantom Misfire Case
I once had a 2010 Buick Lucerne with the 4.6L V8 in my bay that was driving its owner crazy. It had an intermittent misfire on cylinder 3 that would only happen after the car was fully warmed up. The owner had already replaced the plug, the coil, and even the fuel injector, but the problem persisted. My initial scans showed the misfire, but all live data for that cylinder looked perfect right until the moment it would drop out. After ruling out mechanical issues, I focused on the ECM. On a hunch, I monitored the injector driver circuit command from the ECM. Sure enough, after 20 minutes of idling, the signal to the #3 injector became erratic. The ECM’s internal driver was failing under heat. We installed a VIN-programmed module just like this one, and the phantom misfire was gone for good. It’s a classic example of how a failing ECM can send you on a wild goose chase.
Your Straightforward Installation Guide
Replacing the ECM on your Lucerne is a manageable job for a DIYer with basic tools. The module is located in a protected spot, making access fairly simple. Always prioritize safety.
- 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 the 2009-2011 Lucerne, you’ll find the Engine Control Module attached to the lower part of the air cleaner box assembly in the engine bay.
- Access the Module: You may need to remove the top of the air cleaner box to get clear access to the ECM and its wiring harnesses.
- Disconnect the Harnesses: Carefully disengage the locking tabs on the electrical connectors and pull them straight out from the module. Never force them. Inspect the pins for any corrosion or damage.
- Remove the Old ECM: Unbolt the old module from its mounting bracket on the air cleaner box.
- Install the New ECM: Mount your new, pre-programmed module securely in place. Reconnect the electrical harnesses, ensuring they click and lock firmly.
- Final Steps: Reassemble the air cleaner box and any other components you removed. Reconnect the negative battery terminal. The vehicle may need to complete an idle relearn procedure, which typically involves starting the engine and letting it run for a few minutes.
Verified Vehicle Compatibility
This ECM is a guaranteed fit for the 2009-2011 Buick Lucerne with the 4.6L V8 engine. It is also a direct replacement for a wide range of other GM vehicles and is interchangeable with service numbers 12636659, 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. Please see the detailed list below:
CHEVROLET COLORADO 09-12, CORVETTE 09 (ZR1), TRAILBLAZER 09 (6.0L)
GMC CANYON 09-12, ENVOY 09 (5.3L)
HUMMER H3 09-10
SAAB 9-7X 09
Frequently Asked Questions
Frequently Asked Questions
Why do you need my VIN?
Your Vehicle Identification Number (VIN) is essential. We use it to load the exact, correct GM-certified software for your Lucerne’s specific configuration (engine, transmission, options). This ensures the 2009-2011 Lucerne Engine Module works perfectly out of the box, with no extra programming required on your end.
Is this a simple plug-and-play installation?
Yes, because we program it beforehand, the physical installation is plug-and-play. Once installed, you may need to perform a security relearn or crankshaft position sensor relearn, which can often be done without special tools. Instructions are widely available, or your local mechanic can perform it quickly.
Will this fix my car’s specific problem?
This ECM will correct issues directly caused by a faulty engine computer, such as internal processor errors (P0601), communication faults, and failing sensor drivers. While it solves many common problems, we always recommend a proper diagnosis to confirm the ECM is the point of failure before ordering.
Are there any other part numbers this is compatible with?
Absolutely. This module, 12630464, is a direct replacement for several other GM service numbers, including 12636659, 12628993, 12625453, and 12678512, among others listed in our compatibility chart.