If your 2008-2010 Hummer H3 is suffering from harsh shifting, getting stuck in gear, or throwing transmission codes, the culprit is often a failed Transmission Control Module (TCM). As an automotive diagnostician with over two decades of experience, I’ve seen countless GM vehicles, including the rugged H3, sidelined by this exact issue. This VIN-programmed T42 TCM, part number 24240400, is the definitive solution to restore your vehicle’s transmission performance and get you back on and off the road with confidence.
The TCM is the brain of your automatic transmission, controlling everything from shift points to torque converter clutch engagement. When it fails, the symptoms are impossible to ignore and can mimic a catastrophic transmission failure, leading to expensive misdiagnoses. This replacement module is meticulously programmed to your H3’s specific Vehicle Identification Number (VIN) before it ships, ensuring it communicates flawlessly with your vehicle’s other computers right out of the box. This eliminates the need for a costly and time-consuming trip to the dealership for programming.
A Technician’s Notebook
I remember a 2009 H3 that came into the shop stuck in ‘limp mode’—third gear only. The owner was convinced his 4L60E transmission was shot and was bracing for a multi-thousand-dollar bill. A quick scan showed a P0753 (Shift Solenoid ‘A’ Electrical) and the generic P0700 code. While it could have been a solenoid, experience pointed me to the TCM. These modules are known to fail internally, causing erratic voltage to the solenoids and triggering false codes. Instead of tearing down the valve body, we started with the brain. We installed one of these pre-programmed TCMs, cleared the codes, and the H3 was shifting perfectly on the test drive. It saved the customer over a thousand dollars and hours of unnecessary labor.
Is Your H3 Showing These Telltale Signs?
- ✔ Harsh, banging shifts or delayed gear engagement, especially when cold.
- ✔ The vehicle is stuck in a single gear (limp mode) to protect the transmission.
- ✔ An illuminated Check Engine Light or Transmission Warning Light is present on the dash.
- ✔ Your scan tool shows Diagnostic Trouble Codes (DTCs) like P0700, P0750, P0753, P0758, or other solenoid-related faults.
- ✔ Inconsistent shifting, failure to upshift or downshift, and a noticeable drop in fuel economy.
- ✔ Complete loss of communication with the TCM, preventing the vehicle from starting or shifting out of park.
Why Choose a Pre-Programmed 2008-2010 Hummer H3 TCM?
This isn’t just a replacement part; it’s a complete repair solution. By programming the module with the latest GM software updates for your specific VIN, we ensure optimal shift strategy and electronic compatibility. This addresses common factory software bugs and provides a level of precision that a generic, non-programmed module can’t match. Built to meet or exceed original equipment standards and backed by a one-year warranty, it’s a repair you can trust.
Your 30-Minute Path to a Smooth-Shifting H3
- ✔ Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system.
- ✔ Locate the Module: On the Hummer H3, the TCM is typically found in the engine compartment on the right-hand (passenger) side, near the rear of the engine bay.
- ✔ Disconnect and Remove: Carefully unplug the electrical connectors. Press the release tabs firmly. Then, unbolt the old module from its mounting bracket.
- ✔ Install the New TCM: Mount the new module in place and securely tighten the bolts. Reconnect the electrical harnesses, ensuring they click into place.
- ✔ Final Steps: Reconnect the battery terminal. Start the vehicle and use a standard OBD2 scan tool to clear any stored transmission codes. Take the vehicle for a test drive to confirm the shifting issues are resolved.
Verified Vehicle Compatibility
This T42 Transmission Control Module is a direct fit for the following vehicles, but this listing is specifically for the 2008-2010 HUMMER H3. The module is also compatible with a wide range of other GM models, and is interchangeable with part numbers 24252114, 24234503, 24230461, 24240400, and more. Please verify your part number or contact us with your VIN to ensure perfect fitment.
- HUMMER H3: 2008, 2009, 2010 (Transmission; RH rear engine compartment)
- Chevrolet Colorado: 2008-2012
- GMC Canyon: 2008-2012
- And many other GM cars, trucks, and SUVs from 2006-2014.
Frequently Asked Questions
Do I really need to provide my VIN?
Yes. Providing your VIN is essential. We use it to program the module with the exact software and calibrations for your Hummer H3’s specific configuration. This guarantees plug-and-play functionality and optimal transmission performance.
Is this a difficult part for a DIYer to install?
Not at all. This is one of the more straightforward electronic repairs. With basic hand tools, the installation can typically be completed in under 30 minutes. The location in the H3’s engine bay is relatively easy to access.
Will this fix a P0700 code?
A P0700 code is a generic fault code indicating the TCM has detected a problem and requested the check engine light. This module will often resolve the underlying issue causing the P0700, such as internal circuit failure or faulty solenoid commands. However, you should always scan for other, more specific ‘P’ codes to confirm the diagnosis.
What is the warranty on this module?
This module comes with a comprehensive one-year warranty, giving you peace of mind and protection for your investment.
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 at your convenience without the hassle of shipping it back.