If your 2006-2011 Chevrolet HHR is suffering from erratic shifting, getting stuck in gear, or throwing transmission-related trouble codes, the cause is often a failing Transmission Control Module (TCM). As the electronic brain of your automatic transmission, a faulty TCM can disrupt your vehicle’s performance and reliability. This OEM-quality T42 Transmission Control Module, part number 24243901, is the definitive solution, arriving expertly pre-programmed to your vehicle’s specific VIN for a true plug-and-play installation.
Over my two decades in automotive diagnostics, I’ve seen countless GM vehicles, from workhorse vans to daily drivers like the HHR, come into the shop with baffling transmission issues. More often than not, the root cause traces back to this module. This isn’t just a replacement part; it’s a restoration of your vehicle’s core functionality, ensuring precise gear changes, correct torque converter lockup, and stable communication with the Engine Control Module (ECM).
A Technician’s Notebook
I remember a 2009 HHR that came in with the check engine light on and the transmission stuck in 3rd gear—classic limp mode. The owner was worried about a complete transmission failure. After pulling a P0700 (Transmission Control System Malfunction) code, my diagnostics pointed directly to the TCM. The internal electronics had failed due to heat and vibration over the years. Instead of a costly transmission rebuild, we installed a VIN-programmed module like this one. In under 30 minutes, the codes were cleared, and the car was shifting perfectly. It’s a common, straightforward fix that saves customers a fortune.
Common Symptoms of a Failing 2006-2011 HHR TCM
A failing TCM can manifest in several ways. If you’re noticing any of the following issues, it’s a strong indicator that your module needs attention. Ignoring these signs can lead to further transmission damage and unsafe driving conditions.
- âś” Harsh, delayed, or unpredictable gear shifts.
- âś” The vehicle is stuck in a single gear (limp mode).
- âś” Check Engine Light or Transmission Warning Light is illuminated.
- âś” Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults are present.
- âś” A noticeable drop in fuel economy.
- âś” The transmission seems to slip out of gear.
- âś” Complete loss of communication with the scan tool.
DIY Installation: A Step-by-Step Guide
Replacing the TCM on your HHR is a task most DIY enthusiasts can handle in their own garage. No specialized tools are required, and our VIN programming means you won’t need a trip to the dealership.
- Safety First: Before starting, disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s computer systems.
- Locate the Module: On the Chevy HHR, the TCM is typically found in the engine compartment, mounted on the left-hand (driver’s side) of the engine bay.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Press the release tabs firmly. Then, unbolt the module from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed TCM in the same location. Secure the bolts and firmly reconnect the electrical harnesses until they click into place.
- Final Steps: Reconnect the negative battery terminal. Start the vehicle and let it idle for a few minutes. While our programming handles the critical setup, it’s good practice to use a standard OBD2 scan tool to clear any stored fault codes from the previous issue.
Verified Vehicle Compatibility
This T42 TCM is a direct-fit replacement for a wide range of General Motors vehicles equipped with 4-speed automatic transmissions. While this page is focused on the 2006-2011 HHR TCM, it is also compatible with the following models. Always verify your part number (24243901) or contact us with your VIN to ensure perfect fitment.
Fits: Chevrolet HHR (06-11), Cobalt (06-10), Impala (06-11), Monte Carlo (06-07), Malibu (06-10); Pontiac G5/G6 (06-10), Grand Prix (06-08); Saturn Aura (07-09), Ion (06-07), Vue (07-10); Buick Allure/LaCrosse (06-09), Lucerne (06-11); GMC Canyon (08-12); Cadillac DTS (06-11) and many more GM models from 2006-2014.
Frequently Asked Questions
Why is VIN programming so important?
VIN programming loads your vehicle’s exact software and calibrations onto the module before it ships. This ensures it communicates perfectly with your engine, brakes, and other systems right out of the box, eliminating the need for expensive dealership programming.
Is this a difficult part to install myself?
Not at all. For most models like the HHR, it’s a simple bolt-off, bolt-on process in the engine bay that takes less than 30 minutes with basic hand tools. Our pre-programming makes it a true DIY-friendly solution.
Will this fix my P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. In many cases, a faulty TCM is the source of the P0700 and other related codes. Replacing the module with this unit is a very common and effective fix for these issues.
Do I need to return my old part (core charge)?
No, there is no core charge for this part. You can keep or dispose of your old module without any hassle or additional fees.
What is the warranty on this module?
This transmission control module comes with a one-year warranty, giving you confidence and peace of mind in your repair.