Restore Smooth, Reliable Shifting to Your GM Vehicle
If you’re dealing with the frustration of a transmission that won’t shift correctly, bangs into gear, or has left you stranded in limp mode, you’ve come to the right place. This T42 Transmission Control Module (TCM), part number 24240400, is the definitive solution for your 2007-2009 Saturn Aura and a wide range of other GM vehicles. As the brain of your automatic transmission, a failing TCM can cause a cascade of problems that make driving unpleasant and unsafe. This replacement module is expertly pre-programmed to your vehicle’s specific VIN, ensuring it works perfectly right out of the box, with no expensive dealership trips required for programming.
Case Study: A Tricky Diagnosis
I remember a 2008 Saturn Aura that came into my shop with a complaint of intermittent, harsh 1-2 shifts and occasionally getting stuck in 3rd gear. The owner had already replaced a shift solenoid with no luck. A scan showed a generic P0700 code, but no specific solenoid faults were active. After a test drive, I noticed the torque converter lock-up was erratic. In my 20+ years of experience, these ghost-in-the-machine electrical issues almost always point back to the module itself. The internal circuit boards on these T42 TCMs can develop micro-fractures from years of heat and vibration. We installed one of our VIN-programmed modules, and the car drove like new. The customer was thrilled to avoid a costly diagnostic rabbit hole at the dealership.
Is Your Vehicle Showing These Telltale Signs?
A faulty TCM can manifest in several ways. If you’re noticing any of the following, it’s a strong indicator that your module needs replacement:
- ✔ Harsh, slamming, or delayed gear shifts.
- ✔ Vehicle is stuck in one gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is on.
- ✔ Diagnostic Trouble Codes (DTCs) are present, especially P0700, P0750, or other solenoid-related codes.
- ✔ The transmission refuses to upshift or downshift as expected.
- ✔ A sudden drop in fuel economy or signs of the transmission overheating.
A Straightforward Guide to Installation
One of the best features of this module is its simple, DIY-friendly installation. You can get your vehicle back to perfect working order in your own driveway in under 30 minutes.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the system.
- Locate the Module: On the 2007-2009 Saturn Aura, the TCM is typically found on the front of the left frame rail. On other GM models, it could be near the battery, on the LH strut tower, or under the air cleaner box.
- Swap the Part: Carefully unplug the electrical connectors and unbolt the old module. Secure the new module in its place and firmly reconnect the wiring harnesses.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD2 scan tool to clear any stored fault codes from the vehicle’s memory.
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct replacement for a wide array of cars, trucks, and SUVs. It is interchangeable with part numbers 24252114, 24234503, 24230461, 24234274, 24235340, 24235754, 24238856, 24239224, 24239926, 24240400, 24241806, 24243901, 24243921, 24252114, 24255280, 24256960, 24235732, 24235753, 24240449, and YNXS. Please confirm your vehicle is on the list below:
- Saturn Aura: 2007-2009 (LH frame rail front)
- Chevrolet: Cobalt, Colorado, Express, HHR, Impala, Malibu, Monte Carlo, Silverado, Suburban, Tahoe
- GMC: Canyon, Envoy, Savana, Sierra, Yukon
- Buick: Allure, LaCrosse, Lucerne, Rainier, Rendezvous
- Pontiac: G5, G6, Grand Prix, Pursuit
- Cadillac: DTS
- Hummer: H3
- Saab: 9-7X
- And more… (Refer to the detailed fitment list for specific years and options)
Do I need to take my car to the dealer after installing this?
Do I need to take my car to the dealer after installing this?
No. This Transmission Control Module comes pre-programmed to your vehicle’s VIN. This means it is ready for immediate installation and operation without any need for additional dealership programming, saving you time and money.
What’s the benefit of VIN programming?
VIN programming ensures the module has the correct software and calibrations specifically for your vehicle’s configuration (engine, transmission, and other options). This guarantees optimal shift points, torque converter operation, and overall performance, just as the manufacturer intended.
Is this a difficult part for a DIYer to replace?
Not at all. The installation is very straightforward and typically takes less than 30 minutes with basic hand tools. The most common locations are easily accessible in the engine bay, making it an ideal repair for a home mechanic.
Do I need to send my old part back?
No, there is no core charge for this part. You can keep or dispose of your old module without any hassle.
What if my part number is slightly different?
This module is a direct replacement for many GM service numbers. We have provided a comprehensive list of interchangeable part numbers in the description. As long as your part number is on that list, this module will work for you.