If your 2006-2007 Saturn Ion is suffering from erratic shifting, getting stuck in gear, or throwing transmission codes, you’re not just dealing with an annoyance—you’re facing a critical drivability issue. As a technician with over two decades of experience, I’ve seen firsthand how a failing Transmission Control Module (TCM) can sideline a perfectly good vehicle. The TCM is the brain of your automatic transmission, and when it fails, the symptoms can range from poor fuel economy to a complete refusal to shift. This VIN-programmed T42 TCM is the definitive, hassle-free solution to restore your vehicle’s performance and your peace of mind.
A Technician’s Notebook: The Case of the Limp-Mode Ion
A customer brought in a 2007 Saturn Ion, complaining it was stuck in what felt like third gear and the check engine light was on. They were worried about a catastrophic transmission failure. After connecting my scan tool, I pulled a P0700 (Transmission Control System Malfunction) and several solenoid-specific codes. Instead of immediately quoting a costly transmission rebuild, I checked the TCM. These T42 modules are known for internal solder joint failures over time. We replaced it with a VIN-programmed unit like this one. In under an hour, all codes were cleared, and the car was shifting as smoothly as it did from the factory. It’s a common repair that saves drivers from unnecessary, expensive work.
Is Your Saturn Ion Exhibiting These Telltale Signs?
A faulty TCM doesn’t always mean a dead transmission. Often, replacing the module is all that’s needed. Watch for these common indicators of failure:
- ✔ Harsh, slamming shifts or sudden, jerky gear changes.
- ✔ The vehicle enters “limp mode,” refusing to shift out of 2nd or 3rd gear.
- ✔ Check Engine Light or Transmission Warning Light is illuminated on the dash.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, P0758, or other solenoid circuit faults.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ A noticeable drop in fuel efficiency due to improper gear selection.
- ✔ Complete inability to upshift or downshift, making driving unpredictable.
The Benefits of a Pre-Programmed Solution
The biggest challenge with replacing electronic modules used to be the expensive trip to the dealership for programming. Our modules eliminate that step entirely. This isn’t just a part; it’s a complete repair solution. We program the module to your vehicle’s specific VIN before it ships, loading it with the latest GM software updates. This ensures that your new 2006-2007 Ion Transmission Control Module communicates flawlessly with your vehicle’s engine computer and other systems right out of the box. It’s a reliable fix that restores factory shift points, torque converter lockup, and overall transmission health.
Simple 30-Minute Installation Guide
- ✔ Safety First: Always disconnect the negative terminal from your vehicle’s battery before beginning any electrical work. This prevents short circuits and helps reset the vehicle’s electronic systems.
- ✔ Locate the Module: On the 2006-2007 Saturn Ion, the TCM is typically found in the engine bay, mounted behind the driver-side (LH) strut tower.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Press the release tabs firmly to avoid damaging the clips. Then, unbolt the module from its mounting bracket.
- ✔ Install the New Module: Mount the new, pre-programmed TCM in the same location and securely fasten the bolts. Reconnect the electrical connectors, ensuring they click into place.
- ✔ Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s good practice to use a basic OBD-II scan tool to clear any stored fault codes from the system. Start the car and take it for a test drive to confirm smooth shifting.
Verified Fitment for Your General Motors Vehicle
This T42 TCM, part number YNXS, is a direct-fit replacement for a wide range of GM vehicles. While this page focuses on the 2006-2007 Ion Transmission Control Module, it is also compatible with the following models. Please verify your vehicle and part number (interchangeable numbers include 24242391, 24234503, 24252114) for a guaranteed fit.
- Saturn Ion: 2006-2007 (Transmission; behind LH strut tower)
- Chevrolet Cobalt: 2006-2010 (Transmission; LH strut tower)
- Chevrolet HHR: 2006-2011 (Transmission; LH engine compartment)
- Chevrolet Malibu: 2006-2010 (Transmission; LH frame rail)
- Pontiac G6: 2006-2010 (Transmission; 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 after installation?
No. This module is delivered pre-programmed to your vehicle’s VIN. This makes it a true plug-and-play solution, saving you the time, cost, and hassle of a dealership visit for programming.
What tools do I need to install this?
Installation typically only requires basic hand tools, such as a socket set to remove the mounting bolts and potentially a small screwdriver to help release the electrical connector tabs. No specialized electronic tools are needed.
Is this a new or used part?
This is a high-quality, OEM-standard component that has been expertly prepared and programmed for your vehicle. It is inspected and tested to meet or exceed original performance specifications and comes with a one-year warranty.
Will this fix a P0700 code?
A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases where the TCM itself is the source of the electrical fault, replacing it with our programmed module will resolve the P0700 and any related solenoid codes.
Is there a core charge for my old part?
No, we do not require a core return. You can keep your old part, which simplifies the process and saves you the cost and effort of shipping it back.