If you’re dealing with the frustration of a Chevrolet HHR that shifts harshly, gets stuck in gear, or throws transmission-related trouble codes, you’ve come to the right place. As a technician with over two decades of experience under the hood, I’ve seen countless drivers struggle with these exact symptoms, often fearing a costly transmission rebuild. In a vast majority of cases, the culprit isn’t the transmission itself, but its electronic brain: the Transmission Control Module (TCM).
This T42 TCM, part number 24256960, is the definitive solution for your 2006-2011 HHR and a wide range of other GM vehicles. The most critical feature we offer is our expert VIN programming service. Before this module ships, we flash it with your vehicle’s specific VIN and the latest GM software. This means it arrives at your door ready for a true plug-and-play installation, completely bypassing the need for an expensive trip to the dealership for programming. It’s a direct fix that restores the crisp, reliable shifting you expect from your vehicle.
From the Diagnostic Bay
I remember a 2009 HHR that came into my shop with a classic case of intermittent limp mode. The owner was ready to give up, having been told he might need a new transmission. The scanner showed a generic P0700 code, but no specific solenoid faults. After checking the wiring, we swapped in one of our pre-programmed TCMs. The test drive was perfect—smooth upshifts, no hesitation. The problem wasn’t mechanical; it was a failing module causing communication errors. This simple part saved the customer thousands and got a reliable car back on the road.
Diagnosing the Problem: Common HHR TCM Failure Signs
A failing TCM can mimic a variety of serious transmission issues. Before you condemn the transmission, check if your vehicle is displaying any of these classic electronic failure symptoms. Replacing the 2006-2011 HHR TCM is often the most direct and cost-effective repair.
- ✔ Harsh, slamming shifts or delayed gear engagement.
- ✔ The vehicle is stuck in a single gear (limp mode), often 2nd or 3rd.
- ✔ An illuminated Check Engine Light or Transmission Warning Light.
- ✔ Diagnostic Trouble Codes (DTCs) are present, especially P0700 (Transmission Control System Malfunction) or various solenoid codes (e.g., P0751, P0756).
- ✔ Complete loss of upshifting or downshifting capabilities.
- ✔ Noticeably poor fuel economy or a transmission that seems to be overheating.
Get Your HHR Shifting Smoothly: A 30-Minute Install Guide
One of the best parts about this solution is how simple the installation is. For the Chevy HHR, you can have this job done in your driveway in under 30 minutes with basic hand tools.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and help reset the system.
- Locate the TCM: On the 2006-2011 HHR, the TCM is conveniently located in the engine compartment, typically on the driver’s side near the strut tower. It’s a silver box with electrical connectors.
- Disconnect and Remove: Carefully unplug the wiring harnesses. They have locking tabs that need to be released. Then, unbolt the old module from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed TCM into place. Securely plug in the wiring harnesses, ensuring they click to confirm a solid connection.
- Final Steps: Reconnect the battery terminal. While our programming handles the heavy lifting, it’s good practice to use a basic OBD2 scanner to clear any stored fault codes from the vehicle’s memory. Start the engine and enjoy a smooth test drive!
Verified Fitment for Your General Motors Vehicle
This T42 TCM is a direct replacement for part number 24256960 and is interchangeable with numerous other service numbers. While this page focuses on the 2006-2011 HHR TCM, it is also confirmed to fit the following vehicles. Always verify your part number or consult your mechanic to ensure proper fitment.
This part will fit these makes and models with these options:
- 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)
- CHEVROLET SILVERADO & GMC SIERRA (Select 2007-2013 Models) – Transmission; (next to battery)
- PONTIAC G6 (2006-2010) – Transmission; (LH strut tower)
- SATURN AURA (2007-2009) – Transmission; (LH frame rail front)
- …and many other GM cars, trucks, and SUVs from 2006-2014. Please see the full fitment list for details.
Frequently Asked Questions
Do I need to do any programming after I install this TCM?
No. This module is delivered to you fully programmed to your vehicle’s VIN. It is a plug-and-play solution that requires no additional dealership programming or expensive scan tools.
Is this a new or used part?
This is a high-quality, OEM-spec part that has been expertly tested and prepared to ensure reliability. It is backed by our one-year warranty for your peace of mind.
Where is the TCM located on my 2007 Chevy HHR?
For the 2006-2011 Chevrolet HHR, the Transmission Control Module is found in the engine bay, mounted on the driver’s side (LH) in the area of the strut tower.
Will this fix a P0700 trouble code?
Yes, in many cases. The P0700 code is a general fault request from the TCM. If the TCM itself is the source of the electrical fault, replacing it with our programmed module will resolve the root cause and allow the code to be cleared.
Is there a core charge for this part?
No, there is no core charge. You are not required to send your old, faulty module back to us, saving you time and hassle.