Restore Smooth, Reliable Shifting to Your Chevrolet HHR
If your 2006-2011 Chevrolet HHR is suffering from harsh shifting, getting stuck in gear, or throwing transmission-related check engine lights, a failing Transmission Control Module (TCM) is the most likely culprit. As the electronic brain of your automatic transmission, the TCM dictates every gear change and torque converter operation. When it fails, it can make your vehicle unpredictable and unsafe to drive. This OEM-quality T42 TCM, part number 24243921, is the definitive solution, arriving pre-programmed to your vehicle’s VIN for a true plug-and-play repair.
A Technician’s Notebook: The Intermittent HHR Shifting Ghost
I had a 2009 HHR in the shop that was a real head-scratcher. The owner complained of random, violent downshifts on the highway and occasional delayed engagement from a stop. Of course, by the time it got to my bay, it drove perfectly. No active codes, just a stored P0700 (Transmission Control System Malfunction). After checking fluid levels and solenoid resistance, everything seemed fine. On a hunch, I monitored the TCM data stream during a long test drive. Sure enough, I saw the command signals to the solenoids drop out for a split second right before a harsh shift. The internal circuitry of the original 2006-2011 HHR Transmission Module was failing under heat. Swapping in a VIN-programmed module like this one solved the issue permanently. It’s a common failure point I’ve seen dozens of times on these platforms.
Is Your HHR Showing These Transmission Warning Signs?
- ✔ Unpredictable or harsh gear changes.
- ✔ Vehicle feels stuck in one gear (often called “limp mode”).
- ✔ The check engine light is on with codes like P0700, P0750, P0753, or other solenoid-specific faults.
- ✔ Delayed shifting when moving from Park to Drive or Reverse.
- ✔ A noticeable decrease in fuel economy.
- ✔ Complete loss of communication with the transmission module.
A Straightforward Guide to Installation
For the Chevy HHR, this is a repair you can confidently tackle in your own driveway. The entire process typically takes less than 30 minutes.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electronic component replacement.
- Locate the Module: On the 2006-2011 HHR, the TCM is conveniently located in the engine compartment, typically on the driver’s side near the strut tower.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Then, unbolt the module from its mounting bracket.
- Install the New Module: Mount your new, pre-programmed TCM in the same location and securely reconnect the electrical harnesses.
- Final Steps: Reconnect the battery terminal. While our programming handles the critical setup, it’s good practice to use a basic OBD2 scan tool to clear any old stored fault codes from the vehicle’s memory.
Verified Vehicle Compatibility
This module is a direct-fit replacement for the 2006-2011 HHR Transmission Module. It is also compatible with a wide range of other General Motors vehicles that use the T42 TCM, including the Chevrolet Cobalt, Pontiac G6, Saturn Ion, and many others. It directly interchanges with part numbers such as 24234503, 24252114, 24243901, and more, ensuring you get the right part for the job.
Frequently Asked Questions
Do I need to take my vehicle to a dealership for programming?
No. This module comes fully programmed to your vehicle’s specific VIN. It’s ready for installation right out of the box, saving you hundreds in dealership fees and programming costs.
What is the main cause of failure for these modules?
In my experience, the primary causes are heat cycles and vibration. Over years of operation, the sensitive internal electronic components and solder joints can degrade, leading to intermittent connections and eventual failure.
Is this part difficult to install on a Chevy HHR?
Not at all. The TCM on an HHR is located in an easily accessible spot in the engine bay. With basic hand tools, most DIY mechanics can complete the replacement in under 30 minutes.
Do I need to send my old part back (core charge)?
No, there is no core charge for this part. You can keep your old module or dispose of it without any hassle.
Will this fix a P0700 trouble code?
A P0700 code is a general fault code indicating the TCM has detected a problem. If the root cause is a failing TCM, replacing it with this module will resolve the issue and allow the code to be cleared permanently.