End Shifting Nightmares in Your Buick LaCrosse
If you’re dealing with a 2006-2009 Buick LaCrosse that shifts harshly, gets stuck in gear, or throws transmission-related check engine lights, the problem is often not the transmission itself, but its electronic brain. The Transmission Control Module (TCM) is the master controller for all your automatic transmission’s functions. Over my 20+ years in automotive diagnostics, I’ve seen countless vehicle owners worry about needing a costly transmission rebuild when the real culprit was a failing TCM—a much simpler and more affordable fix.
This T42 Transmission Control Module is the definitive solution for your vehicle. It arrives expertly programmed to your car’s specific Vehicle Identification Number (VIN), making it a true plug-and-play replacement. You can bypass the expensive and time-consuming trip to the dealership for programming. Simply install it, and restore the crisp, predictable shifting your LaCrosse had when it was new.
Case Study: A Tricky Diagnosis
A customer brought in a 2008 Buick LaCrosse with a classic complaint: intermittent ‘limp mode’ and a check engine light with a P0700 code (Transmission Control System Malfunction). Another shop had already replaced a shift solenoid with no success and was quoting him for a full transmission tear-down. Before going down that expensive path, I checked the TCM. Sure enough, communication with the module was dropping out when the engine bay got hot. We installed one of our pre-programmed T42 modules, and the problem was solved in under an hour for a fraction of the quoted cost. It’s a perfect example of why you should always suspect the TCM in these GM vehicles.
Is Your Buick LaCrosse Showing These Telltale Signs?
- ✔ Harsh, slamming shifts or erratic gear changes.
- ✔ The vehicle is stuck in a single gear (limp mode), often 2nd or 3rd.
- ✔ Check Engine Light or Transmission Warning Light is on with codes like P0700, P0750, or other solenoid-related DTCs.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Failure to upshift or downshift properly, leading to poor acceleration.
- ✔ A noticeable decrease in fuel economy.
A Straightforward Guide to Your LaCrosse TCM Installation
Replacing the 2006-2009 LaCrosse TCM is a job most DIYers can handle in their own garage. For this specific model, you’ll find the module located under the lower air cleaner housing.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic work.
- Access the Module: Remove the air cleaner box assembly to gain clear access to the TCM mounted below it.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Bolt the new, pre-programmed module into place and securely reconnect the electrical harnesses. You should hear a click as they lock in.
- Reassemble and Finalize: Reinstall the air cleaner housing. Reconnect the battery terminal. Start the vehicle and use a basic scan tool to clear any stored fault codes.
Verified Vehicle Compatibility List
This module, part number 24240449, is a direct replacement for a wide range of General Motors vehicles. While this page focuses on the 2006-2009 LaCrosse TCM, it also fits models like:
- Buick Allure (06-09), Lucerne (06-11)
- Chevrolet Cobalt (06-10), HHR (06-11), Impala (06-11), Malibu (06-10), Monte Carlo (06-07)
- Chevrolet Silverado & GMC Sierra Trucks (Check specific years/options)
- Chevrolet Tahoe & GMC Yukon (Check specific years/options)
- Pontiac G6 (06-10), Grand Prix (06-08)
- Saturn Aura (07-09), Ion (06-07), Vue (07-10)
- And many more. Please verify your part number or contact us to confirm fitment.
Does this TCM require programming at a dealership?
Does this TCM require programming at a dealership?
No, it does not. We program the module to your vehicle’s VIN before shipping. It arrives ready for a plug-and-play installation, saving you time and money.
Where is the TCM located on my 2007 Buick LaCrosse?
On the 2006-2009 Buick LaCrosse, the Transmission Control Module is typically found under the lower air cleaner housing in the engine bay.
Will this part fix a P0700 trouble code?
A P0700 code indicates a general fault within the transmission control system. A failing TCM is one of the most common causes for this code. Replacing a faulty TCM with this part is a very common and effective solution for clearing a P0700 and related transmission codes.
Is there a core charge for my old part?
No, there is no core charge. You can keep or dispose of your old module without the hassle of sending it back.