If your 2006-2007 Saturn ION is suffering from erratic shifting, getting stuck in gear, or throwing 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 ION, sidelined by a faulty T42 TCM. This isn’t just an annoyance; it’s a critical failure that compromises your car’s performance and safety. This module is the solution—a direct-fit, OEM-quality replacement that comes fully programmed to your vehicle’s specific VIN, eliminating the need for an expensive trip to the dealership.
This part, also known by service numbers like 24252114 and 24234503, is the brain of your automatic transmission. It precisely controls shift solenoids, manages torque converter lockup, and communicates with the main engine computer to ensure smooth, efficient operation. When it fails, you get the classic symptoms of confusion: harsh bangs into gear, delayed shifts, or the dreaded “limp mode.” Our 2006-2007 ION TCM restores that lost communication, giving you back the crisp, predictable shifting you expect.
Is Your Saturn ION Showing These Telltale Signs?
- ✔ Harsh, jerky, or delayed gear shifts.
- ✔ The vehicle is stuck in a single gear (limp mode) to protect the transmission.
- ✔ Check Engine Light or Transmission Warning Light is on with codes like P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid errors), or other communication faults.
- ✔ Complete loss of shifting capability, either up or down.
- ✔ A noticeable drop in fuel economy due to inefficient gear management.
- ✔ Intermittent electrical problems that seem to have no other cause.
Case Study: A Tricky Diagnosis
A customer brought in a 2007 Saturn ION with an intermittent shifting problem. It would drive perfectly for days, then suddenly refuse to shift out of 2nd gear. They had already replaced two shift solenoids at another shop with no success. After hooking up my scan tool and monitoring live data, I saw the command signals from the TCM were dropping out randomly. The wiring and solenoids were fine; the TCM itself was failing internally under certain thermal conditions. We installed one of our VIN-programmed T42 modules, and the problem was solved instantly. It’s a classic example of why throwing parts at a problem doesn’t work—a proper diagnosis points to the right solution.
A Straightforward Guide to Installation
For the 2006-2007 Saturn ION, this is a repair most DIY enthusiasts can handle in their own driveway. The module is typically located behind the driver’s side (LH) strut tower in the engine bay, making it accessible without major disassembly.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- Locate the Old TCM: Find the module behind the LH strut tower. It will have several large electrical connectors attached.
- Disconnect and Remove: Carefully unclip the wiring harnesses. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Securely reconnect the wiring harnesses, ensuring they click into place.
- Final Steps: Reconnect the battery terminal. While our programming handles the critical setup, it’s good practice to use a basic OBD2 scanner to clear any stored fault codes from the ECU. Start the vehicle and test drive to confirm smooth shifting.
Verified Vehicle Compatibility List
This T42 TCM is a direct replacement for part number 24240449 and is compatible with a wide range of General Motors vehicles. While this page focuses on the 2006-2007 ION TCM, it also fits other models. Please verify your part number or consult the list below for your specific application.
- Saturn ION: 2006-2007 (Behind LH strut tower)
- Saturn Vue: 2007-2010 (Location varies by engine/drivetrain)
- Saturn Aura: 2007-2009 (LH frame rail front)
- Chevrolet Cobalt: 2006-2010 (LH strut tower)
- Chevrolet HHR: 2006-2011 (LH engine compartment)
- Pontiac G5/G6: 2006-2010 (LH strut tower)
- …and many other GM cars, trucks, and SUVs from 2006-2014.
Frequently Asked Questions
Do I need to take my car to the dealer for programming?
No. This module comes pre-programmed to your vehicle’s VIN. It is a true plug-and-play solution, saving you the time and expense of a dealership visit. Just provide your VIN at checkout.
Is this part difficult to install on a Saturn ION?
Not at all. For the ION, the TCM is located in an accessible spot in the engine bay. With basic hand tools, most people can complete the swap in under 30 minutes.
What is the warranty on this TCM?
This part is backed by our standard one-year, unlimited mileage warranty, giving you peace of mind and confidence in your repair.
Will this fix a P0700 trouble code?
A P0700 code simply means the TCM has detected a fault and requested the check engine light. If the underlying fault (like a failing solenoid driver or internal short) is within the TCM itself, then yes, replacing the module will resolve the cause of the P0700 code.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old part or recycle it locally without the hassle of shipping it back to us.