Restore Smooth Shifting to Your Chevrolet HHR
If you’re dealing with the frustration of a transmission that won’t shift correctly, gets stuck in gear, or triggers a check engine light in your 2006-2011 Chevrolet HHR, a failing Transmission Control Module (TCM) is often the culprit. As a technician with over two decades of experience, I’ve seen countless GM vehicles, especially compacts like the HHR, suffer from erratic behavior due to a faulty TCM. Heat and vibration in the engine bay take their toll over time, leading to internal circuit failures that disrupt communication between your engine and transmission. This isn’t just an annoyance; it affects fuel economy, performance, and safety.
This T42 TCM, part number 24234274, is the definitive solution. It’s not just a replacement part; it’s a complete fix that arrives pre-programmed to your HHR’s specific Vehicle Identification Number (VIN). This means you can skip the expensive trip to the dealership for programming. It’s a true plug-and-play component designed to restore the precise, factory-intended operation of your automatic transmission. By correctly managing shift points, torque converter lockup, and line pressure, this module eliminates the guesswork and gets your vehicle driving like new again.
From the Diagnostic Bay: The Intermittent HHR Shifting Nightmare
I remember a 2009 HHR that came into my shop with a problem that was driving the owner crazy. The car would drive perfectly for days, then suddenly start shifting hard from 1st to 2nd and refuse to go into overdrive. The check engine light was on, but the codes were intermittent solenoid faults. The owner had already replaced two shift solenoids with no luck. After connecting my scan tool and monitoring live data, I noticed the TCM was intermittently dropping communication. This is a classic sign of a failing module. We installed one of our VIN-programmed T42 modules, and the problem was solved instantly. The live data was stable, the codes cleared, and the car shifted flawlessly. It’s a textbook example of why throwing parts at a problem rarely works—proper diagnosis points to the brain, the TCM, being the root cause.
Key Signs Your HHR Transmission Module is Failing
- ✔ Your HHR is stuck in “limp mode,” often refusing to shift out of 2nd or 3rd gear.
- ✔ The Check Engine Light or a transmission-specific warning light is illuminated on your dash.
- ✔ You’re experiencing harsh, delayed, or unpredictable gear shifts.
- ✔ Diagnostic trouble codes (DTCs) like P0700, P0750, P0751, or other solenoid-related faults are present.
- ✔ A noticeable drop in fuel efficiency or a transmission that feels like it’s slipping.
- ✔ The vehicle fails to engage a gear from Park or Neutral.
A Straightforward Guide to DIY Installation
Replacing the 2006-2011 HHR Transmission Module is a job most DIY enthusiasts can handle in their own garage in under 30 minutes. The module is conveniently located and requires only basic hand tools.
- Safety First: Begin by disconnecting the negative terminal from your vehicle’s battery to prevent any electrical shorts and help reset the vehicle’s computer systems.
- Locate the Module: On the Chevrolet HHR, the TCM is typically found in the left-hand (driver’s side) of the engine compartment, often near the strut tower or air cleaner box.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old TCM. Press the release tabs firmly to avoid breaking them. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, VIN-programmed TCM into place. Reconnect the electrical harnesses, ensuring they click securely into position.
- Final Steps: Reconnect the negative battery terminal. While our VIN programming handles the critical setup, it’s always good practice to use a basic OBD2 scan tool to clear any stored fault codes from the system. Start the vehicle and take it for a test drive to confirm smooth shifting.
Will This Fit My Vehicle?
This T42 TCM is a direct-fit replacement for a wide range of General Motors vehicles. While this listing focuses on the 2006-2011 HHR, it is also compatible with the following models. Please verify the location described matches your vehicle.
- Chevrolet: HHR (06-11), Cobalt (06-10), Impala (06-11), Malibu (06-10), Monte Carlo (06-07), Colorado (08-12), Silverado, Tahoe, Suburban, Avalanche, Express Van
- GMC: Canyon (08-12), Sierra, Yukon, Savana Van
- Pontiac: G5 (07-10), G6 (06-10), Grand Prix (06-08)
- Saturn: Aura (07-09), Ion (06-07), Vue (07-10)
- Buick: LaCrosse (06-09), Allure (06-09), Lucerne (06-11)
- And many more, including select Cadillac, Hummer, and Saab models. This part interchanges with numbers like 24252114, 24234503, and 24230461.
Do I need to program this module after I receive it?
No. This is the biggest benefit of our service. We pre-program the module to your vehicle’s VIN before shipping. It arrives ready for a plug-and-play installation, with no need for a trip to the dealer or a specialized scan tool for programming.
Where is the TCM located on my 2008 HHR?
On most 2006-2011 HHR models, the Transmission Control Module is located in the engine compartment on the driver’s side (LH side), near the strut tower. It’s an accessible location that makes for a quick replacement.
Is there a core charge for my old part?
No, there is no core charge. You are not required to send your old, faulty module back to us, saving you time and return shipping costs.
What if I have a P0700 code?
A P0700 code is a general transmission fault request from the TCM to the main engine computer (ECM) to turn on the Check Engine Light. It almost always appears alongside other, more specific transmission codes (like solenoid or pressure switch faults). Replacing a faulty TCM often resolves the P0700 and the specific codes causing it.
What kind of warranty is included?
This module comes with a one-year warranty, giving you peace of mind that you’re investing in a quality, reliable part for your vehicle’s repair.