Restore Peak Performance to Your Buick Lucerne
Is your 2009-2011 Buick Lucerne suffering from frustrating issues like a persistent Check Engine Light, rough idling, stalling, or poor fuel economy? These are classic signs of a failing Engine Control Module (ECM), the central computer of your vehicle. A faulty ECM can disrupt everything from fuel delivery to transmission shifting, making your car unreliable and stressful to drive. This isn’t just an inconvenience; it’s a critical component failure that needs a dependable solution.
We offer a straightforward, reliable fix: a professionally prepared 2009-2011 Lucerne ECM, part number 12636659. The biggest hurdle in replacing an ECM is the programming, which typically requires an expensive trip to the dealership. We eliminate that step entirely. Simply provide us with your vehicle’s VIN during checkout, and our technicians will program the module with the latest official GM software updates specifically for your car. It arrives at your door ready for installation, saving you significant time and money.
A Technician’s Notebook: The Intermittent Stall
I once had a 2010 Lucerne in my bay that was a real head-scratcher. The owner complained of random stalling at stoplights, but with no consistent Check Engine Light codes. We checked the fuel pressure, throttle body, and sensors—all were fine. The issue was so intermittent it was nearly impossible to replicate. On a hunch, I monitored the ECM’s live data streams and noticed occasional, erratic voltage drops within the module itself, just before it would command a shutdown. It was the ECM failing internally under specific thermal conditions. Replacing it with a properly programmed unit solved the problem instantly. This experience taught me that with modern electronics, sometimes the subtlest symptoms point to the brain, not the body.
Common Signs of a Failing Engine Computer
If you’re experiencing any of the following, a failing ECM could be the culprit. A replacement is often the most direct path to resolving these issues and preventing further component damage.
- âś” Persistent Check Engine Light (CEL)
- âś” Engine stalling or misfiring unexpectedly
- âś” Noticeable decrease in fuel efficiency
- âś” Car won’t start, despite a good battery and starter
- âś” Rough or inconsistent shifting in an automatic transmission
- âś” Communication error codes, such as P0601, P0606, or U0100
- âś” Failure to pass emissions testing
Your Straightforward Installation Guide
Installing your new 2009-2011 Lucerne ECM is a manageable task for a DIYer. For the Lucerne, the ECM is conveniently located at the lower part of the air cleaner box.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts.
- Access the Module: Locate and remove the air cleaner assembly to gain clear access to the old ECM.
- Disconnect and Remove: Carefully unplug the wiring harness connectors from the old module. Press the release tabs firmly. Then, unbolt the module from its mounting bracket.
- Install the New ECM: Mount the new module in the same position and securely fasten the bolts. Reconnect the wiring harnesses, ensuring they click into place.
- Reassemble: Reinstall the air cleaner assembly and any other components you removed.
- Reconnect Battery: Reattach the negative battery terminal.
- Perform Security Relearn: You will need to perform a simple key-on/key-off security relearn procedure. This syncs the new ECM to your vehicle’s anti-theft system. A quick online search for “GM security relearn procedure” will provide the exact steps (it typically involves turning the key to ‘ON’ for 10-15 minutes, then ‘OFF’, and repeating a few times).
Verified Fitment Across Multiple GM Models
This ECM, with service number 12636659, is a direct replacement for a wide range of GM vehicles and is interchangeable with part numbers 12639300, 1263605, 12628993, 12628911, 12625453, 12622175, 12630464, and 12678512. Please verify your vehicle is on this list:
- âś” Buick Lucerne (4.6L): 2009-2011
- âś” Cadillac CTS (6.2L): 2009
- âś” Cadillac DTS: 2009-2011
- âś” Cadillac SRX (4.6L): 2009
- âś” Cadillac STS (4.4L, 4.6L): 2009-2010
- âś” Cadillac XLR (ID 12636659, 12625453): 2009
- âś” Chevrolet Colorado (2.9L, 3.7L): 2009-2012
- âś” Chevrolet Corvette (ZR1): 2009
- âś” Chevrolet Trailblazer (6.0L): 2009
- âś” GMC Canyon (2.9L, 3.7L): 2009-2012
- âś” GMC Envoy (5.3L): 2009
- âś” Hummer H3 (3.7L): 2009-2010
- âś” Saab 9-7x: 2009
Frequently Asked Questions
Do I need to do any programming myself?
No. We handle all the programming before shipping. Just provide your VIN when you order, and the module will arrive with the correct GM software for your specific vehicle, ready for installation and the security relearn procedure.
Why do you need my VIN?
Your Vehicle Identification Number (VIN) allows us to access the exact factory software and calibration files for your car’s specific options and configuration. This ensures perfect compatibility and performance, just like a new part from the dealer.
Is the security relearn procedure difficult?
Not at all. It’s a simple process that anyone can do and requires no special tools. It typically involves a sequence of turning the ignition key to the ‘ON’ and ‘OFF’ positions for set periods. This procedure is essential for allowing your vehicle to start after the new ECM is installed.
Will this fix my check engine light?
If the check engine light is caused by an internal failure of the ECM (common codes P0601-P0606), then yes, this part will resolve the issue. However, if the light is on due to a faulty sensor or other component, that separate issue will still need to be addressed.
Is this a genuine GM part?
This is a quality, tested original equipment part that has been inspected and programmed by our expert technicians to meet or exceed original factory specifications. It is a reliable and cost-effective alternative to a brand new module from a dealership.