Is Your GMC Yukon Shifting Erratically or Stuck in Limp Mode?
If you’re dealing with the frustration of a transmission that won’t shift correctly, slams into gear, or has left you stranded with a check engine light, a faulty Transmission Control Module (TCM) is the most likely culprit. In my 20+ years as a technician, I’ve seen these exact issues on countless GM trucks. The TCM is the brain of your automatic transmission, and when it fails, it can make your 2007-2009 Yukon feel unpredictable and unsafe to drive. This T42 TCM, part number 24235340, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a true plug-and-play repair.
Real-World Diagnostic Story
“A customer’s 2008 Yukon came into my shop last month with classic signs of a bad TCMโharsh 1-2 shift and intermittent ‘Transmission Hot’ warnings, even when it wasn’t. He was convinced he needed a new module. Before ordering the part, I did a quick visual inspection. On these Yukons, the TCM is located right next to the battery. I noticed some greenish-white corrosion on the main harness connector pins from battery acid fumes over the years. We spent 10 minutes cleaning the pins with a terminal brush and electrical contact cleaner, and the problems vanished. Always check and clean your TCM connectors before replacing the moduleโit could save you hundreds!”
Symptoms of a Failing 2007-2009 Yukon Transmission Control Module
A failing TCM doesn’t just degrade performance; it can cause a cascade of issues. Hereโs what I see most often in the shop:
- โ Harsh Shifting & Delayed Engagement: The vehicle jerks or bangs into gear, or there’s a long pause when shifting from Park to Drive or Reverse.
- โ Stuck in One Gear (Limp Mode): The transmission defaults to 2nd or 3rd gear to prevent further damage, resulting in poor acceleration and high RPMs.
- โ Warning Lights: The Check Engine Light or a specific transmission warning light is illuminated on your dash.
- โ Diagnostic Trouble Codes (DTCs): You’ll often find codes like P0700 (Transmission Control System Malfunction) or various solenoid-specific codes (e.g., P0750, P0751).
- โ No Communication: A scan tool may be unable to communicate with the TCM, indicating a complete module failure.
Plug-and-Play Installation: No Dealer Visit Required
One of the biggest benefits of this module is our in-house VIN programming. We flash the unit with the latest GM software for your exact Yukon before it ships. This means you can install it yourself in your driveway or have your local mechanic do it without needing an expensive trip to the dealership for programming. The installation is straightforward:
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and help reset the system.
- Locate the TCM: On the 2007-2009 GMC Yukon, the TCM is typically mounted in a bracket right next to the battery in the engine compartment.
- Disconnect and Remove: Carefully unclip the electrical harness connectors. Press the release tabs firmly. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical harnesses. You should hear a ‘click’ as they lock in.
- Reconnect and Verify: Reconnect the battery terminal. Start the vehicle and check for smooth shifting and ensure no warning lights are present. We recommend using a basic scan tool to clear any stored fault codes after installation.
OEM-Quality and Broad Compatibility
This module is built to meet or exceed original equipment standards for reliability and longevity. While it’s the perfect fit for your Yukon, it also serves as a direct replacement for a wide range of GM vehicles using the T42 controller, including the Chevrolet Tahoe, Silverado, Suburban, and many more. It interchanges with numerous part numbers, including 24252114, 24234503, 24242391, and 24235340, ensuring you get the right part for the job.