Restore Smooth Shifting to Your Chevy HHR
If your 2006-2011 Chevrolet HHR is suffering from erratic shifting, getting stuck in gear, or has an illuminated check engine light, a failing Transmission Control Module (TCM) is the most likely culprit. As a technician with over two decades of experience, I’ve seen countless GM vehicles, including the HHR, come into the shop with these exact issues. The problem often isn’t the transmission itself, but this critical electronic brain. This OEM-quality T42 TCM, part number 24241806, is the definitive solution to restore your vehicle’s performance and reliability without a costly trip to the dealership.
The TCM is the nerve center of your automatic transmission, managing everything from shift points and line pressure to torque converter lockup. When it fails, communication breaks down, leading to the frustrating and sometimes dangerous symptoms you’re experiencing. Our module arrives pre-programmed to your HHR’s specific Vehicle Identification Number (VIN), ensuring it works perfectly right out of the box. This eliminates the need for expensive programming tools or dealer intervention, making it a straightforward fix for both professional mechanics and determined DIYers.
Case Study: A Tricky Diagnosis
A customer brought in their 2009 HHR with classic ‘limp mode’ symptoms—stuck in 3rd gear with a P0700 code. Another shop had quoted them over $2,500 for a transmission rebuild. After a quick scan and data stream analysis, I noticed erratic solenoid command signals originating from the TCM. The transmission fluid was clean and the internal mechanics were sound. We swapped in a VIN-programmed T42 module, cleared the codes, and the car shifted perfectly. The customer saved thousands and was back on the road in under an hour. It’s a textbook example of how correctly diagnosing the 2006-2011 HHR TCM can prevent unnecessary, expensive repairs.
Is Your HHR Showing These Transmission Problems?
- ✔ Harsh, banging shifts or delayed gear engagement.
- ✔ The vehicle is stuck in a single gear (limp mode) and won’t shift up or down.
- ✔ Check Engine Light or Transmission Warning Light is on with codes like P0700, P0750, P0755, or other solenoid-related faults.
- ✔ A noticeable drop in fuel economy due to inefficient shifting.
- ✔ Complete loss of communication with the transmission module, preventing diagnostics.
- ✔ Intermittent failure to shift, which gets worse as the vehicle warms up.
A Straightforward Guide to Installation
Replacing the 2006-2011 HHR TCM is a job most people can handle in their own driveway in about 30 minutes. For the HHR, the module is conveniently located in the left-hand (driver’s side) engine compartment, making access easy.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent electrical shorts and reset the system.
- Locate the Module: Find the TCM on the driver’s side of the engine bay. It will have several large electrical connectors attached.
- Disconnect and Remove: Carefully unclip the wiring harness connectors. Then, unbolt the module from its mounting bracket and remove it from the vehicle.
- Install the New TCM: Mount your new, VIN-programmed module in the same location. Securely reconnect all wiring harnesses, ensuring they click into place.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s best practice to use a basic OBD2 scan tool to clear any stored diagnostic trouble codes (DTCs) from the computer’s memory.
Verified Vehicle Compatibility List
This T42 Transmission Control Module is a direct-fit replacement for a wide range of General Motors vehicles. While this page focuses on the 2006-2011 HHR TCM, it is also compatible with the following models. Please verify your specific model and part number before ordering.
- Chevrolet: HHR (06-11), Cobalt (06-10), Impala (06-11), Malibu (06-10), Monte Carlo (06-07), Tahoe (07-09), Silverado (07-13), Express Van (06-14), and more.
- GMC: Sierra (07-13), Yukon (07-09), Savana Van (06-14), Envoy (06-09), Canyon (08-12).
- Pontiac: G6 (06-10), G5 (07-10), Grand Prix (06-08), Pursuit (06).
- Saturn: Aura (07-09), Vue (07-10), Ion (06-07).
- Buick: LaCrosse (06-09), Lucerne (06-11), Allure (06-09), Rendezvous (06-07).
- Cadillac: DTS (06-11).
- And others including: Hummer H3, Saab 9-7X, Isuzu Ascender.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for my HHR?
It means we load your vehicle’s unique 17-digit VIN into the module before shipping. This ensures it has the correct software and calibration for your specific engine, transmission, and options, making it a true plug-and-play part with no dealer visit required.
Do I need to send my old TCM back?
No, there is no core charge for this part. You can keep or dispose of your old module, saving you the time and hassle of a return shipment.
Will this fix a P0700 trouble code?
A P0700 code is a generic fault request from the TCM to the main engine computer (ECM) to turn on the check engine light. While this module often resolves the underlying issue causing the P0700, it’s crucial to scan for more specific transmission codes (like P07xx) to confirm the diagnosis.
Is this a difficult part to install myself?
For most DIYers with basic tools, this is a very manageable repair. The HHR’s module location is accessible, and the process involves simple unplugging and unbolting. Following our installation guide should make the process smooth and successful.
What if I have questions during installation?
Our team of experts is here to help. We provide support to ensure you can get your vehicle repaired correctly. Your purchase is backed by our expertise and a one-year warranty for peace of mind.