Is your 2006-2010 Pontiac G6 driving you crazy with unpredictable shifting, getting stuck in gear, or a persistent Check Engine light? Before you start worrying about a costly transmission rebuild, the problem is very often the brain of the operation: the Transmission Control Module (TCM). As a technician with over two decades of experience, I’ve seen countless GM vehicles, including the G6, exhibit these exact symptoms. The culprit is frequently a failing T42 TCM, which can disrupt communication and cause chaos in your drivetrain.
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We take a high-quality, OEM-spec T42 TCM (interchangeable with part number 24234503) and professionally program it to your vehicle’s specific VIN. This crucial step ensures that the module communicates flawlessly with your car’s engine computer and other systems right out of the box, restoring the smooth, reliable performance you expect from your Pontiac.
A Technician’s Notebook
I remember a customer bringing in a 2008 G6 with classic ‘transmission failure’ symptoms: banging into gear, refusing to shift past 2nd, and a dash lit up with warnings. Another shop had quoted them over $3,000 for a transmission replacement. I hooked up my scan tool and saw a slew of solenoid circuit codes and the dreaded P0700 (Transmission Control System Malfunction). From experience, I know these T42 modules are prone to internal circuit failure. Instead of a massive mechanical job, we swapped in a VIN-programmed TCM. In under an hour, the car was shifting perfectly. The customer saved thousands, all because we correctly identified the electronic failure point first.
Is Your G6 Showing These Telltale Signs?
A failing TCM doesn’t always mean total failure. It often starts with intermittent issues that get progressively worse. Watch out for these common indicators:
- ✔ Harsh, slamming, or jerky gear shifts.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Vehicle is stuck in “limp mode” (usually second or third gear).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) stored, such as P0700, P0750, or other solenoid-related faults.
- ✔ Failure to upshift or downshift properly, leading to poor acceleration and fuel economy.
A Straightforward Guide to Installation
For the Pontiac G6, this is a very DIY-friendly repair that you can complete in your driveway. The TCM is typically located on the driver’s side of the engine bay, mounted to the strut tower. No complex tools are needed.
- Safety First: Disconnect the negative terminal from your car’s battery to prevent any electrical shorts and help reset the vehicle’s computer systems.
- Locate the Module: Open the hood and find the TCM on the driver’s side (LH) strut tower. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unclip the wiring harness connectors. Then, unbolt the module from its mounting bracket. There are usually just a few bolts holding it in place.
- Install the New TCM: Mount your new, pre-programmed module onto the bracket and securely fasten the bolts. Reconnect the wiring harnesses, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. Start the vehicle and allow it to idle for a few minutes. While not always necessary, using a basic OBD2 scanner to clear any old fault codes is a good final practice.
Verified Vehicle Compatibility
This T42 TCM is a direct-fit, programmed solution for a wide range of General Motors vehicles. While this listing is focused on the 2006-2010 G6 TCM, it is also compatible with the following models. Please verify your part number (24234503) for a perfect match.
- Pontiac: G6 (06-10), G5 (07-10), Grand Prix (06-08), Montana (06-09), Pursuit (06), Solstice (06-10), Torrent (06-09)
- Chevrolet: Cobalt (06-10), HHR (06-11), Impala (06-11), Malibu (06-10), Monte Carlo (06-07), Tahoe, Silverado, Express Van, and more.
- Buick: LaCrosse (06-09), Lucerne (06-11), Allure (06-09)
- Saturn: Aura (07-09), Ion (06-07), Vue (07-10)
- And many other GM, GMC, Hummer, and Saab models using the T42 TCM.
Frequently Asked Questions
What exactly does ‘VIN Programmed’ mean for me?
It means we load your car’s unique Vehicle Identification Number (VIN) and the latest GM software onto the module before shipping. This makes it a true plug-and-play part, eliminating the need for expensive programming at a dealership.
Do I need any special tools for this installation?
No. For a Pontiac G6, the installation typically only requires basic hand tools like a socket set to remove the mounting bolts. The most important part is ensuring the battery is disconnected before you begin.
Will this part fix a P0700 trouble code?
A P0700 code is a general fault request from the TCM to the main engine computer. While a faulty TCM is a very common cause for this code, it’s important to scan for other transmission-specific codes (like P07xx) to confirm the diagnosis. In many cases, replacing a bad TCM will resolve the P0700 code.
Where is the TCM located on my 2008 Pontiac G6?
On the 2006-2010 Pontiac G6, the Transmission Control Module is conveniently located in the engine compartment, mounted to the driver’s side (LH) strut tower.
Is there a core charge for my old part?
No, there is no core charge required for this module. You can keep your old part, so there’s no need to worry about return shipping or waiting for a refund.