Is Your GMC Yukon’s Transmission Acting Up?
If you’re dealing with a GMC Yukon that bangs into gear, refuses to shift, or has its check engine light glaring at you, a faulty Transmission Control Module (TCM) is a likely culprit. As a technician with over two decades of experience, I’ve seen these symptoms countless times. The TCM is the brain of your automatic transmission, and when it starts to fail, it can make your reliable SUV feel unpredictable and unsafe. This isn’t just an annoyance; it’s a critical failure that impacts drivability, fuel economy, and the long-term health of your transmission.
This T42 Transmission Control Module is the definitive solution for your 2007-2009 Yukon Transmission Control Module problems. It arrives at your door expertly programmed to your vehicle’s specific VIN. This means you can skip the expensive trip to the dealership for programming. It’s a true plug-and-play fix designed for both professional mechanics and determined DIYers who want to get their truck back to factory-smooth operation without the hassle.
Case Study: A Tricky Diagnosis
A customer brought in a 2008 Yukon with classic symptoms: harsh 1-2 shifts and an intermittent P0752 (Shift Solenoid ‘A’ Stuck On) code. They had already replaced the solenoid inside the transmission pan—a messy and costly job—but the problem persisted. After a quick data scan, I noticed the TCM was commanding the solenoid erratically. The internal drivers on the original module had failed. We installed one of our pre-programmed T42 TCMs, and in less than 30 minutes, the Yukon was shifting perfectly. This highlights how a faulty module can mimic internal transmission problems, making proper diagnosis key.
Is Your Yukon Exhibiting These Telltale Signs?
A failing TCM doesn’t just get better on its own. Watch for these common indicators that it’s time for a replacement:
- ✔ Abrupt, harsh, or jerky gear shifts.
- ✔ The vehicle feels stuck in one gear (often called “limp mode”).
- ✔ Check Engine Light is on with transmission-related Diagnostic Trouble Codes (DTCs) like P0700, P0750, P0752, or other solenoid circuit codes.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Complete loss of communication with the module, preventing shifting.
- ✔ A noticeable drop in fuel efficiency.
A Mechanic’s Guide to a 30-Minute Installation
Replacing the 2007-2009 Yukon Transmission Control Module is a straightforward job you can do in your own garage. The location can vary slightly, but it’s typically found in the engine bay for easy access.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the system.
- Locate the Module: On most Yukons and Tahoes, you’ll find the TCM mounted next to the battery in the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly. Then, unbolt the module from its mounting bracket.
- Install the New TCM: Bolt the new, pre-programmed module into place and securely reconnect the electrical harnesses. You should hear a click as they lock in.
- 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 enjoy the restored performance.
Verified Fitment For These GM Vehicles
This T42 TCM is a direct replacement for part number 24255280 and is interchangeable with many other service numbers. It is compatible with a wide range of General Motors cars, trucks, and SUVs equipped with 4-speed automatic transmissions (4L60E, 4L65E, 4L70E, etc.). While this page focuses on the 2007-2009 Yukon Transmission Control Module, it also fits the following models (check location notes for specifics):
- GMC: Yukon, Yukon XL, Sierra 1500/2500, Savana 1500/2500/3500, Envoy, Canyon
- Chevrolet: Tahoe, Suburban 1500, Silverado 1500/2500, Avalanche 1500, Express 1500/2500/3500, Impala, Monte Carlo, Cobalt, HHR, Colorado, Malibu, SSR
- Cadillac: DTS
- Buick: LaCrosse, Lucerne, Allure, Rainier, Rendezvous
- Pontiac: G5, G6, Grand Prix, Pursuit
- Saturn: Vue, Aura, Ion
- Hummer: H3
- Saab: 9-7X
Frequently Asked Questions
Frequently Asked Questions
Do I need to take my vehicle to the dealer after installation?
No. This module is delivered pre-programmed to your vehicle’s VIN. It is a true plug-and-play solution, saving you hundreds in dealership fees and programming time.
What is a T42 TCM?
The T42 is the specific hardware platform used by General Motors for the transmission control module in a wide range of vehicles from roughly 2006 to 2014, primarily managing 4-speed automatic transmissions.
Is this part difficult to install myself?
Not at all. For most DIYers with basic hand tools, this is a job that takes less than 30 minutes. The module is typically located in an easy-to-access spot in the engine bay.
What happens if I don’t replace a failing TCM?
Continuing to drive with a bad TCM can cause poor performance, terrible fuel economy, and eventually lead to catastrophic damage to the mechanical parts of your transmission, resulting in a much more expensive repair.
Is there a core charge for my old part?
No, there is no core charge. You can keep your old module or dispose of it without the hassle of sending it back.