Restore Your LaCrosse’s Performance and Reliability
As a technician with over two decades of experience, I’ve seen firsthand how a failing Engine Control Module (ECM) can turn a reliable car into a source of constant frustration. If your 2010-2011 Buick LaCrosse is suffering from perplexing issues like random stalling, poor fuel economy, a persistent Check Engine Light, or erratic shifting, the ECM is often the root cause. It’s the brain of your vehicle, and when it starts to falter, the symptoms can be widespread and confusing. This isn’t just a part; it’s the central command center for your engine’s performance and efficiency.
This replacement Engine Control Module, part number 12642665, is the definitive solution to get your vehicle running smoothly again. We take the guesswork and hassle out of the repair by programming the module specifically for your car before it even leaves our facility. Simply provide us with your vehicle’s VIN (Vehicle Identification Number) after your purchase, and our specialists will flash it with the latest GM-certified software updates. This ensures perfect communication between the module and your car’s systems, restoring original factory performance without a costly trip to the dealership for programming.
A Technician’s Notebook: The Ghost in the Machine
I remember a 2011 LaCrosse that came into the shop with a laundry list of complaints. The owner reported intermittent no-start conditions, occasional harsh shifts, and a check engine light that threw codes for the throttle body, a transmission solenoid, and even an O2 sensor. The parts cannon had already been fired at it with no success. After hooking up my scan tool and monitoring live data, I noticed the 5-volt reference signal would occasionally drop out for a split second—a classic sign of an internal ECM failure. The module was shorting internally, sending phantom signals and causing other components to report errors. We installed a pre-programmed ECM like this one, and every single issue vanished. It’s a powerful reminder that sometimes, the problem lies with the conductor, not the orchestra.
Diagnosing a Faulty Engine Computer
- âś” Check Engine Light: A constant or flashing check engine light is the most common sign. Codes like P0601 (Internal Control Module Memory Check Sum Error) or P0606 (ECM/PCM Processor Fault) are direct indicators.
- âś” Engine Performance Problems: You might experience stalling, rough idling, misfiring, or a noticeable decrease in power and fuel efficiency.
- âś” Starting Issues: The vehicle may crank but refuse to start, or fail to crank at all, even with a good battery and starter.
- âś” Transmission Glitches: The ECM works with the Transmission Control Module (TCM). A failing ECM can cause harsh or delayed shifting.
- âś” Communication Errors: You might see a U0100 (Lost Communication With ECM/PCM) code, indicating other modules on the vehicle can’t talk to the engine computer.
A Straightforward Guide to Installation
Installing your new 2010-2011 LaCrosse ECM is a manageable job for a confident DIYer. Since we handle the programming, you won’t need any special scan tools for the initial setup. Just follow these steps carefully.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery and wait a few minutes to ensure the system is fully discharged.
- Locate the ECM: On the 2010-2011 LaCrosse, the ECM is typically found in the engine compartment on the driver’s side (LH side), often near the fuse box or air filter housing.
- Disconnect the Connectors: Carefully release the locking tabs on the wiring harness connectors and pull them straight out from the module. Never force them. Inspect the pins for any corrosion or damage.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket. Keep the hardware, as you’ll need it for the new module.
- Install the New Module: Mount the new, pre-programmed ECM onto the bracket and secure it with the original bolts.
- Reconnect Everything: Firmly plug the wiring harnesses back into the new ECM until they click into place. Reconnect the negative battery terminal.
- Final Steps: Some vehicles may require a security relearn procedure, which can often be done by cycling the key. It’s also a good practice to clear any old codes with a basic code reader after installation.
Verified Vehicle Compatibility
This module is a direct replacement for several part numbers and fits a wide range of GM vehicles. Please verify your vehicle and part number below. This unit is compatible with service numbers: 12616889, 12630908, 12637106, 12642665, 12650256, and 12651993.
- Buick Allure: 2010 (2.4L & 3.0L)
- Buick LaCrosse: 2010-2011 (2.4L & 3.0L)
- Buick Regal: 2011
- Cadillac CTS: 2010-2012 (3.0L & 3.6L)
- Cadillac SRX: 2010-2011 (3.0L)
- Chevrolet Camaro: 2012 (3.6L)
- Chevrolet Captiva Sport: 2012
- Chevrolet Equinox: 2010-2011
- Chevrolet Impala: 2012
- Chevrolet Orlando: 2012-2013
- GMC Terrain: 2010-2011
- Saab 9-5: 2010-2011 (2.0L)
Frequently Asked Questions
How does the programming process work?
After you place your order, you’ll need to send us your 17-digit VIN. Our technicians use this number to access the latest official GM software for your specific vehicle and flash it onto the module. This ensures it’s ready for installation right out of the box.
Is any additional programming needed after I install it?
In most cases, no. Because we program it to your VIN, it’s a plug-and-play solution. However, some vehicles may require a simple security or anti-theft system relearn procedure, which typically involves cycling the ignition key and can be done without special tools. Instructions can easily be found online for your specific model.
Will this fix my specific problem?
This module corrects issues directly caused by a faulty ECM. While symptoms like stalling or no-starts are common indicators, it’s always best to have a proper diagnosis performed. If your mechanic has confirmed the ECM is the problem, or you have diagnostic codes like P0601 or P0606, this is the correct solution.
What is the difference between an ECM and a PCM?
ECM stands for Engine Control Module, while PCM stands for Powertrain Control Module. In many modern vehicles, the terms are used interchangeably. A PCM controls both the engine and the transmission, while an ECM technically only controls the engine. This part functions as the primary engine computer for the vehicles listed.
Why is providing my VIN so important?
Your VIN allows us to load the exact software calibration that your vehicle had when it left the factory. This includes details about the engine, transmission, emissions equipment, and other options. Without the correct VIN-specific programming, the module will not function correctly and may even prevent the car from starting.