Restore Flawless Shifting to Your Chevrolet HHR
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 issues. The problem often points directly to a failing Transmission Control Module (TCM). This VIN-programmed T42 TCM, service number 24234503, is the reliable, straightforward fix you need to get your vehicle’s transmission operating like new again, without a costly trip to the dealership for programming.
The TCM is the brain of your automatic transmission, responsible for every shift command, torque converter clutch engagement, and fluid pressure adjustment. When it fails, the symptoms can range from annoying to dangerous. This module is the definitive solution for a properly diagnosed 2006-2011 HHR TCM failure, restoring the communication between your engine and transmission for smooth, predictable performance.
Case Study: A Tricky Diagnosis
I remember a 2009 HHR that came into my shop with a complaint of intermittent, bone-jarring shifts from 1st to 2nd gear, but only after it was fully warmed up. The owner had already replaced a shift solenoid with no luck. A scan showed a P0752 code (Shift Solenoid ‘A’ Stuck On), but electrical tests on the solenoid and wiring were inconclusive. Experience told me to look at the TCM. After swapping in one of our VIN-programmed modules, the problem was gone instantly. Heat soak in the engine bay had caused an internal fault in the original TCM that only appeared under specific conditions—a classic failure mode for these units.
Is Your HHR Showing These Red Flags?
A failing TCM will give you clear warning signs. If you’re experiencing any of the following, a replacement is likely the answer. Over my years in diagnostics, these are the most common symptoms I’ve linked directly to a bad 2006-2011 HHR TCM:
- âś” Unpredictable, harsh, or delayed gear shifts that make driving uncomfortable.
- âś” The vehicle enters ‘limp mode,’ often getting stuck in 2nd or 3rd gear.
- âś” Your check engine light is on with Diagnostic Trouble Codes (DTCs) like P0700, P0750, P0752, or other solenoid-related faults.
- âś” A complete loss of shifting ability, either refusing to upshift or downshift.
- âś” A noticeable drop in fuel economy as the transmission operates inefficiently.
- âś” Intermittent loss of communication with the module, causing erratic behavior.
Your 30-Minute Path to a Smooth Ride
One of the best features of this module is its simple, DIY-friendly installation. Because we program it to your vehicle’s VIN before shipping, you don’t need any special dealer tools. For the Chevy HHR, the process is especially straightforward.
- Safety First: Always disconnect the negative terminal from your vehicle’s battery before starting any electrical work.
- Locate the TCM: On the 2006-2011 HHR, the Transmission Control Module is typically found in the left-hand (driver’s side) of the engine compartment, 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: Bolt the new, pre-programmed TCM into place and securely reconnect the electrical connectors. You should hear a ‘click’ as they lock in.
- Reconnect and Verify: Reconnect the battery terminal. Start the vehicle and allow it to idle for a moment. Use a basic OBD2 scanner to clear any stored fault codes and take it for a test drive to confirm smooth shifting.
Verified Fitment Across the GM Family
While this is the perfect solution for your HHR, this T42 TCM is also compatible with a wide range of other General Motors vehicles. Please verify your part number (24234503) or contact us to ensure perfect fitment. This module fits many models, including:
- âś” Chevrolet Cobalt, HHR, Impala, Malibu, Monte Carlo
- âś” Pontiac G5, G6, Grand Prix
- âś” Saturn Aura, Ion, Vue
- âś” Buick Allure, LaCrosse, Lucerne
- âś” GMC Canyon, Envoy, Savana, Sierra
- âś” Cadillac DTS
- …and many more models from 2006-2014.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means this module is ready for installation right out of the box. We flash it with your vehicle’s specific Vehicle Identification Number (VIN) and the latest GM software. This ensures it communicates perfectly with your car’s other computers, saving you from a mandatory and expensive programming session at a dealership.
Do I need to send my old TCM back?
No. This part is sold without a core charge. You can keep your old module, which simplifies the process and saves you the hassle and cost of return shipping.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request, meaning the TCM has detected a problem and asked the main computer (ECM) to turn on the check engine light. While this module often resolves the underlying cause (like a solenoid circuit fault stored in the TCM), you should always diagnose any other specific codes that accompany the P0700 to be certain.
Is this a difficult part to install myself?
Not at all. For a DIY enthusiast with basic hand tools, this is a very manageable job. On the HHR, the module is easily accessible in the engine bay, and the entire process typically takes less than 30 minutes.
What if I have a different part number on my original module?
This module (24234503) is a service replacement for many other GM part numbers. Check the compatibility list in our description or contact our expert support team with your original part number to confirm it’s the correct replacement for your vehicle.