If you’re dealing with the frustration of a GMC Yukon that’s shifting erratically, getting stuck in gear, or throwing transmission codes, you’ve come to the right place. As a technician with over two decades of experience, I’ve seen countless GM trucks and SUVs sidelined by a failing Transmission Control Module (TCM). This isn’t just an inconvenience; it affects your vehicle’s performance, fuel economy, and safety. This T42 TCM, part number 24240400, is the definitive, hassle-free solution for your 2007-2008 Yukon XL 1500 TCM issues, arriving pre-programmed to your specific VIN for a true plug-and-play repair.
Case Study: A Tricky Diagnosis
A customer brought in their ’07 Yukon XL 1500, complaining it was stuck in what felt like third gear—a classic sign of “limp mode.” The check engine light was on, and my scan tool pulled a generic P0700 (Transmission Control System Malfunction). Digging deeper, I found intermittent solenoid communication faults. While some shops might start by replacing solenoids inside the transmission pan, my experience pointed straight to the TCM. These modules, exposed to engine bay heat and vibrations, are a common failure point. We installed a VIN-programmed T42 module, cleared the codes, and the truck was shifting perfectly on the test drive. The customer saved hundreds by avoiding unnecessary transmission work and a trip to the dealer for programming.
Is Your Yukon Exhibiting These Transmission Problems?
A failing TCM can manifest in several ways. If you’re noticing any of the following, it’s a strong indicator that your 2007-2008 Yukon XL 1500 TCM needs replacement:
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ The vehicle is stuck in a single gear (limp mode) and won’t shift up or down.
- ✔ Check Engine Light or Transmission Warning Light is illuminated on the dash.
- ✔ Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults are present.
- ✔ A noticeable drop in fuel efficiency or signs of the transmission overheating.
- ✔ Complete loss of communication with the transmission module.
Straightforward Installation for Your Yukon XL
One of the best features of this module is its ease of installation. You don’t need to be a master mechanic to get your truck back on the road. For the Yukon XL, the process is simple and can be done in your driveway in under 30 minutes.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the TCM: On your 2007-2008 Yukon XL 1500, the TCM is conveniently located in the engine compartment, right next to the battery.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. 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.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it’s always best practice to use a basic scan tool to clear any stored DTCs from the vehicle’s memory.
Verified Compatibility for Your GM Vehicle
This T42 TCM is a direct replacement for part number 24240400 and is interchangeable with numerous other service numbers. It provides a reliable fix for a wide range of GM vehicles equipped with 4-speed automatic transmissions like the 4L60E, 4L65E, and 4L70E. While this page is focused on the 2007-2008 Yukon XL 1500 TCM, this part also fits:
- GMC: Sierra 1500/2500, Yukon, Savana, Envoy, Canyon
- Chevrolet: Silverado 1500/2500, Tahoe, Suburban, Avalanche, Express, Impala, Cobalt, HHR, Colorado
- 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
What does “VIN Programmed” actually mean?
It means we load your vehicle’s unique 17-digit Vehicle Identification Number (VIN) and the latest GM-certified software onto the module before we ship it. This ensures it communicates perfectly with your vehicle’s engine computer and other systems right out of the box, eliminating the need for expensive dealership programming.
Do I need to send my old TCM back? Is there a core charge?
No. We do not require a core return for this part. You can keep your old module or dispose of it, making the process simpler and more convenient for you.
Can a bad TCM cause my transmission to fail completely?
Yes, it can. A faulty TCM can cause prolonged improper shifting, leading to excessive clutch wear, overheating, and eventual mechanical failure of the transmission. Replacing a failing TCM promptly is a critical preventative measure.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases, the problem is the TCM itself. If your diagnostics point to a faulty module, this part is the correct solution to resolve the P0700 code and any related transmission codes.