If your 2006-2010 Pontiac G6 is suffering from erratic shifting, getting stuck in gear, or has the check engine light on with transmission codes, you’ve likely pinpointed the culprit: a failing Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen countless GM vehicles, including the G6, come into the bay with these exact issues. The T42 TCM is the brain of your automatic transmission, and when it falters, it can make your car feel unreliable and unsafe to drive. This isn’t just a part; it’s the solution to restore the crisp, predictable performance your car once had.
This isn’t a generic, one-size-fits-all module. We take the hassle and expense out of the equation by pre-programming this unit to your vehicle’s specific VIN. This means you can skip the costly trip to the dealership for programming. It arrives at your door ready for a true plug-and-play installation, loaded with the latest GM software updates to ensure optimal communication between your engine and transmission. By replacing your faulty unit with this quality-tested 2006-2010 G6 Transmission Module, you’re not just fixing a symptom—you’re addressing the root cause of poor fuel economy, harsh engagement, and frustrating limp mode events.
A Technician’s Notebook
I remember a 2008 Pontiac G6 that came in with a classic complaint: “It bangs into gear, but only when it’s warm.” The owner had already replaced a shift solenoid with no luck. A quick scan showed a P0700 (Transmission Control System Malfunction) and an intermittent solenoid circuit code. Experience told me to look beyond the solenoid itself. We checked the wiring and found no issues. The problem was the T42 TCM, which was failing under heat soak. After installing one of our VIN-programmed modules—a 25-minute job—the car shifted perfectly, hot or cold. It’s a textbook example of how this single part can solve a chain of frustrating, hard-to-diagnose symptoms.
Is Your Pontiac G6 Showing These Telltale Signs?
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ Vehicle is stuck in “limp mode,” often in 2nd or 3rd gear.
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700, P0750-P0758, or other solenoid-related faults are present.
- ✔ Complete failure to upshift or downshift, leading to poor acceleration.
- ✔ A noticeable drop in fuel efficiency.
- ✔ Intermittent loss of communication with the TCM.
DIY-Friendly Installation Guide for Your G6
Installing your new 2006-2010 G6 Transmission Module is a straightforward process that most DIYers can complete in under 30 minutes with basic hand tools. For the G6, it’s conveniently located.
- Safety First: Disconnect the negative terminal from your car’s battery to prevent any electrical shorts and to help reset the vehicle’s adaptive memory.
- Locate the TCM: On the Pontiac G6, the module is typically found mounted on the LH (driver’s side) strut tower in the engine bay. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unclip the wiring harness connectors. Then, unbolt the mounting hardware holding the old module in place and remove it from the vehicle.
- Install the New Module: Mount your new, pre-programmed TCM in the same location and secure it with the original hardware. Reconnect the wiring harnesses, ensuring they click securely into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a few minutes. If you have a basic scan tool, it’s good practice to clear any stored DTCs. Take the car for a test drive to confirm the shifting issues are resolved.
Verified Fitment Beyond the Pontiac G6
While this is the perfect solution for your Pontiac G6, this T42 TCM is also compatible with a wide range of other GM vehicles. It is interchangeable with part numbers 24252114, 24234503, 24238856, and others. Key compatible models include:
- ✔ Pontiac: G5, Grand Prix, Pursuit, Montana
- ✔ Chevrolet: Cobalt, HHR, Impala, Malibu, Monte Carlo, Silverado, Tahoe
- ✔ Saturn: Aura, Ion, Vue
- ✔ Buick: Allure, LaCrosse, Lucerne
- ✔ GMC: Canyon, Envoy, Sierra, Yukon
- …and many more models from 2006-2014. Please verify the part number for your specific application.
Frequently Asked Questions
2006-2010 G6 Transmission Module
Is this the same as an Engine Control Module (ECM)?
No, they are different components. The TCM specifically controls transmission functions like shifting and torque converter lockup, while the ECM (or PCM) manages engine operations. A faulty will cause shifting problems, not engine running issues.