Is your Pontiac G5 shifting erratically, getting stuck in gear, or throwing a check engine light? These are classic signs of a failing Transmission Control Module (TCM). As the electronic brain of your automatic transmission, a faulty TCM can make driving frustrating and unsafe. I’ve seen it countless times in the shop: a perfectly good transmission crippled by a bad module. This isn’t just an inconvenience; ignoring it can lead to poor fuel economy and even permanent transmission damage.
This T42 series Transmission Control Module is the definitive, reliable solution for your 2007-2010 Pontiac G5. The most significant benefit is our professional VIN programming service. Before we ship it, we flash the module with your vehicle’s specific VIN and the latest GM software. This means it arrives ready for a true plug-and-play installation, eliminating the need for an expensive trip to the dealership for programming. You get a direct-fit part that restores precise shifting, torque converter lockup, and communication with the rest of your car’s electronics.
From the Diagnostic Bay: The Case of the Stubborn Cobalt
A customer brought in a 2009 Chevy Cobalt (a sister platform to the G5) with a classic complaint: it would randomly refuse to shift out of 2nd gear and the transmission light was on. They’d already replaced a shift solenoid with no luck. A quick scan showed a P0700 (Transmission Control System Malfunction) and an intermittent solenoid circuit code. After 20 years of wrenching, I know these symptoms often point away from the transmission itself and straight to the TCM. We swapped in one of our VIN-programmed T42 modules. The installation took less than 30 minutes, and after clearing the codes, the car shifted like it just rolled off the factory floor. The customer saved hundreds by avoiding a dealership visit and unnecessary parts swapping.
Common Red Flags of a Failing TCM
If your vehicle is exhibiting any of these behaviors, a failing TCM is the likely culprit. A new module can resolve these issues and prevent further complications.
- âś” Hard, jerky, or delayed gear shifts.
- âś” Vehicle is stuck in ‘limp mode’ (usually 2nd or 3rd gear).
- âś” Check Engine Light or Transmission Warning Light is illuminated.
- âś” Diagnostic Trouble Codes (DTCs) are present, especially P0700, P0750, or other solenoid-related codes.
- âś” Failure to upshift or downshift properly.
- âś” A sudden drop in fuel efficiency.
- âś” Complete loss of communication with the module (no-start or no-shift condition).
A Straightforward Guide to Your G5 TCM Swap
This installation is designed to be simple for both DIY enthusiasts and professional technicians. For the Pontiac G5, the TCM is typically located on the driver’s side strut tower, making it easily accessible.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s computer systems.
- Locate the Module: Find the TCM on the left (driver’s side) strut tower in the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors. Note the tab locations to avoid damage. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new VIN-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock in.
- Final Steps: Reconnect the battery terminal. Start the vehicle and let it idle for a few minutes. While the module is pre-programmed, it’s always good practice to use a basic OBD2 scan tool to clear any stored fault codes.
Verified Vehicle Compatibility List
This module, part number YNXS, is a direct-fit replacement for the following vehicles and configurations. Please confirm your model and location before ordering.
- Pontiac G5: 2007, 2008, 2009, 2010 (Transmission; LH strut tower)
- Chevrolet Cobalt: 2006-2010 (Transmission; LH strut tower)
- Chevrolet HHR: 2006-2011 (Transmission; LH engine compartment)
- Saturn Ion: 2006-2007 (Transmission; behind LH strut tower)
- Pontiac G6: 2006-2010 (Transmission; LH strut tower)
- And many other GM models from 2006-2014. Please see the full fitment list for details.
Frequently Asked Questions
Why is VIN programming so important?
VIN programming loads your vehicle’s specific software onto the module. This ensures it communicates correctly with the engine computer, ABS, and other systems, guaranteeing correct shift points, torque converter operation, and overall performance without needing a dealership visit.
Is this a difficult part to replace myself?
No, this is a great DIY-friendly repair. On the Pontiac G5, the TCM is located in an easy-to-access spot on the driver’s side strut tower. With basic hand tools, the swap typically takes less than 30 minutes.
Do I need to return my old TCM? (Core Charge)
No core charge is required. You can keep, recycle, or dispose of your old module without the hassle of sending it back.
Will this fix a P0700 trouble code?
Yes. A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases, replacing a faulty TCM with this pre-programmed unit will resolve the underlying issue and allow the code to be cleared permanently.
What if I have questions during installation?
We’re here to help. Our team of experts has hands-on experience with these parts and can provide support to ensure your repair is successful. Contact us with any questions.