Restore Smooth Shifting to Your Trailblazer
If your 2006-2009 Chevrolet Trailblazer is suffering from harsh shifts, getting stuck in gear, or throwing transmission codes, the problem often points directly to a failing Transmission Control Module (TCM). As the electronic brain of your automatic transmission, the T42 TCM is responsible for every gear change, torque converter lockup, and diagnostic check. When it falters, drivability and reliability suffer. This replacement TCM, part number 24252114, is the definitive, hassle-free solution to get your SUV back to performing as it should.
As a technician with over two decades of experience, I’ve seen countless GM vehicles, from workhorse Silverados to family-hauling Trailblazers, crippled by a bad TCM. The symptoms can be intermittent and frustrating, but the fix doesn’t have to be. We take the biggest headache out of the equation: programming. Each module is expertly programmed to your vehicle’s specific VIN before it ships, ensuring it works perfectly right out of the box. No expensive trips to the dealership, no special scan tools required for setup—just a straightforward replacement.
Case Study: A Tricky Diagnosis
A customer brought in their ’08 Trailblazer with a complaint that it would randomly get stuck in 3rd gear (limp mode), especially after getting hot. The check engine light was on with a generic P0700 code. After checking the fluid and wiring, my diagnostics pointed to an internal TCM fault. These T42 modules are known to develop issues from heat cycles and vibration over the years. We installed one of our pre-programmed modules, and the problem was solved in under an hour. The customer saved hundreds compared to the dealership quote and drove away with a truck that shifted like new. This is the exact fix for that common scenario.
Is Your Trailblazer Exhibiting These Telltale Signs?
A failing TCM will give clear warnings. If you’re experiencing any of the following, it’s time to consider a replacement. Ignoring these symptoms can lead to more significant transmission damage.
- ✔ Harsh, banging, or erratic gear shifts.
- ✔ The vehicle is stuck in a single gear (often called “limp mode”).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700 (Transmission Control System Malfunction), P0750-P0758 (Shift Solenoid errors), or other transmission-related codes.
- ✔ Delayed engagement when shifting from Park to Drive or Reverse.
- ✔ Poor acceleration and decreased fuel economy.
A Straightforward Guide to Installation
One of the best features of this part is its ease of installation. For the 2006-2009 Trailblazer TCM, the process is simple enough for a confident DIYer to complete in their driveway. You’ll find it located in the engine compartment on the driver’s side.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- Locate the TCM: On the 2006-2009 Trailblazer, the TCM is mounted in the left-hand (driver’s side) engine compartment. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unplug the electrical harnesses. 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. Ensure they click into place.
- Reconnect and Verify: Reconnect the negative 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 lingering codes from memory.
Verified Vehicle Compatibility List
This T42 TCM is a direct replacement for part number 24252114 and is interchangeable with many other service numbers. While this page focuses on the 2006-2009 Trailblazer, it also fits a wide range of other GM vehicles. Please verify your vehicle is on this list before ordering.
- Chevrolet Trailblazer: 2006-2007 (8 cylinder), 2008-2009 (All) – Located in LH engine compartment.
- GMC Envoy: 2006-2007 (8 cylinder), 2008-2009 (All) – Located in LH engine compartment.
- Chevrolet Silverado 1500 / GMC Sierra 1500: 2007-2013 (Gas engines, non-hybrid) – Located next to battery.
- Chevrolet Tahoe / GMC Yukon: 2007-2009 (non-hybrid) – Located next to battery.
- Chevrolet Impala: 2006-2011 – Located under lower air cleaner housing.
- Chevrolet HHR: 2006-2011 – Located in LH engine compartment.
- Pontiac G6: 2006-2010 – Located on LH strut tower.
- …and many more GM cars, trucks, and SUVs from 2006-2014.
No. This is the biggest benefit we offer. We program the module to your vehicle’s VIN before shipping, so it arrives ready for plug-and-play installation. This saves you time and the high cost of dealership programming.
On the 2006-2009 Trailblazer, as well as the GMC Envoy and Saab 9-7X, the Transmission Control Module is conveniently located in the engine bay on the driver’s side (LH side).
A P0700 code is a general fault code indicating the TCM has detected a problem. While this module often resolves the root cause (like an internal failure that also triggers solenoid codes), you should ensure other components like wiring and solenoids are in good condition. In many cases, a faulty TCM is the primary culprit.
No, there is no core charge. You can keep your old part or dispose of it without the hassle of returning it, simplifying your repair process.
This T42 TCM is designed for vehicles equipped with GM’s 4-speed automatic transmissions, including the popular 4L60E, 4L65E, and 4L70E found in the Trailblazer and many other GM trucks and SUVs of this era.