Restore Smooth Shifting to Your Chevy HHR
If you’re dealing with the frustration of a Chevrolet HHR that shifts harshly, gets stuck in gear, or illuminates the check engine light, you’re likely facing a failing Transmission Control Module (TCM). As an experienced technician, I’ve seen countless GM vehicles, especially the versatile HHR, sidelined by these exact issues. The TCM is the brain of your automatic transmission, and when it falters, it can make your daily drive unpredictable and unsafe. This isn’t just an inconvenience; it’s a critical failure that impacts fuel economy, vehicle reliability, and your peace of mind.
This replacement T42 TCM, part number 24240449, is the definitive solution. We take the guesswork and dealership hassle out of the repair by pre-programming the module to your vehicle’s specific VIN. This means it arrives at your door ready for a true plug-and-play installation, restoring the precise, factory-intended communication between your engine and transmission. By replacing your faulty unit, you’re not just fixing a part; you’re restoring the dependable performance you expect from your HHR.
From the Diagnostic Bay
I remember a 2009 HHR that came into my shop with a baffling set of symptoms. The owner reported random stalling at stop lights and erratic shifting that would come and go. His local mechanic had already replaced a shift solenoid with no improvement. After hooking up my scan tool, I saw a generic P0700 code but also intermittent communication loss codes (U-codes). Instead of chasing electrical gremlins through the harness, my experience pointed directly to the TCM. Heat cycles and vibrations in the HHR’s engine bay often cause internal solder joints in the module to fail. We installed a VIN-programmed TCM, and the car drove perfectly. It’s a classic case where the root cause is the central controller, not the mechanical parts it commands.
Is Your HHR Showing These Telltale Signs?
A failing TCM can manifest in several ways. If you’re experiencing any of the following, it’s a strong indicator that your 2006-2011 HHR Transmission Module needs replacement:
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ The vehicle is stuck in “limp mode” and won’t shift out of 2nd or 3rd gear.
- ✔ An illuminated Check Engine Light or Transmission Warning Light.
- ✔ Diagnostic Trouble Codes (DTCs) such as P0700, P0750, P0753, or other solenoid-related faults.
- ✔ Complete loss of shifting capability or failure to go into gear.
- ✔ Poor acceleration and a noticeable drop in fuel efficiency.
A Straightforward Guide to Installation
One of the best parts about this solution is its simplicity. For the Chevy HHR, this is a job most DIYers can complete in their driveway in under 30 minutes. Here’s a basic guide:
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the system’s memory.
- Locate the TCM: On the 2006-2011 HHR, the Transmission Control Module is typically found in the engine compartment, mounted on the driver’s side (LH) near the strut tower or under the air cleaner box.
- 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: Bolt the new, pre-programmed TCM into place. Reconnect the electrical harnesses, ensuring they click securely into place.
- Final Steps: Reconnect the battery terminal. While our programming handles the critical setup, it’s always good practice to use a basic OBD-II scan tool to clear any stored fault codes from the vehicle’s memory. Start the car and take it for a test drive to confirm smooth operation.
Verified Vehicle Compatibility
This module is a direct replacement for part number 24240449 and other interchangeable numbers. It is designed for a wide range of General Motors vehicles. While this page focuses on the 2006-2011 HHR Transmission Module, it also fits the following models. Please verify your specific model and location before ordering.
- Chevrolet HHR (2006-2011): Transmission; (LH engine compartment)
- Chevrolet Cobalt (2006-2010): Transmission; (LH strut tower)
- Chevrolet Impala (2006-2011): Transmission; (lower air cleaner housing)
- Chevrolet Malibu (2006-2010): Transmission; (LH frame rail)
- Pontiac G6 (2006-2010): Transmission; (LH strut tower)
- Saturn Aura (2007-2009): Transmission; (LH frame rail front)
- Saturn Ion (2006-2007): Transmission; (behind LH strut tower)
- …and many other GM cars, trucks, and SUVs from 2006-2014.
Frequently Asked Questions
Frequently Asked Questions
What exactly does ‘VIN Programmed’ mean?
It means we load your vehicle’s unique 17-digit Vehicle Identification Number (VIN) and the latest GM software onto the module before we ship it. This ensures it communicates perfectly with your car’s other computers right out of the box, eliminating the need for an expensive trip to the dealership for programming.
Is this a difficult part to install myself?
Not at all for most people with basic tools. On the HHR, it’s located in an accessible part of the engine bay. The entire process of swapping the module typically takes less than 30 minutes. No special tools are required.
Do I need to send my old part back (core charge)?
No, there is no core charge for this module. You can keep your old part or dispose of it responsibly without any extra hassle or fees.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. While a faulty TCM is a very common cause, this code can also be triggered by other transmission issues. Replacing the TCM often resolves the P0700 and any related specific codes (like for solenoids), but you should ensure the transmission itself is mechanically sound.
What is your warranty policy on this module?
This Transmission Control Module comes with a one-year warranty, giving you confidence and peace of mind in your repair.