Restore Peak Performance to Your Chevrolet HHR’s Transmission
Is your 2006-2011 Chevrolet HHR suffering from frustrating transmission problems? Symptoms like harsh, delayed, or erratic shifting, getting stuck in one gear (limp mode), or an illuminated Check Engine Light can point directly to a failing Transmission Control Module (TCM). This genuine OEM-quality T42 TCM, part number 24256960, is the definitive solution to restore the precise, smooth operation you expect from your vehicle. As the electronic brain of your automatic transmission, the TCM is responsible for managing shift points, torque converter clutch engagement, and line pressure, making its proper function critical for both performance and longevity.
From the Diagnostic Bay
We recently had a 2009 Chevy HHR come in with a classic complaint: it would randomly slam into gear and the transmission warning light was on. The owner had already spent money at another shop replacing a couple of shift solenoids, but the problem persisted. A quick scan showed a P0700 code (Transmission Control System Malfunction) and intermittent communication errors with the TCM. Instead of throwing more parts at the transmission itself, we identified the root cause: the original TCM was failing internally. After installing one of our VIN-programmed T42 modules, the vehicle shifted perfectly. The codes were cleared and never returned. This is a common scenario where diagnosing the electronics first saves the customer time, money, and unnecessary mechanical repairs.
Common Symptoms of a Failing HHR Transmission Control Module
A faulty TCM can manifest in various ways, often mimicking mechanical transmission failure. If you’re experiencing any of the following, your TCM is the likely culprit:
- ✔ Harsh or Erratic Shifting: The vehicle may bang into gear, hesitate, or shift at the wrong times.
- ✔ Stuck in Limp Mode: The transmission may refuse to shift out of 2nd or 3rd gear as a protective measure.
- ✔ Warning Lights: The Check Engine Light or a specific transmission warning light will illuminate on your dash.
- ✔ Diagnostic Trouble Codes (DTCs): Common codes include P0700, P0750, or other solenoid-related faults.
- ✔ Delayed Engagement: A noticeable delay when shifting from Park into Drive or Reverse.
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter lockup can lead to a significant drop in MPG.
- ✔ No Communication: A scan tool may be unable to communicate with the transmission module, indicating a total failure.
The Plug-and-Play Advantage: Pre-Programmed for Your HHR
This isn’t just a replacement part; it’s a complete, ready-to-install solution. We pre-program each module to your vehicle’s specific Vehicle Identification Number (VIN) before it ships. This crucial step ensures that the TCM has the latest GM software and is perfectly calibrated for your HHR’s engine, transmission, and tire size. This eliminates the need for an expensive trip to the dealership for programming, allowing for a straightforward installation right out of the box. Simply provide your VIN at checkout, and we handle the rest.
Installation and Compatibility
For the 2006-2011 Chevrolet HHR, the TCM is typically located in the engine compartment on the driver’s side (LH). Installation is simple for a DIY mechanic or any professional technician. After disconnecting the battery, unplug the electrical connectors, unbolt the old module, and install the new one in its place. Once reconnected, use a standard scan tool to clear any stored DTCs. This module is also a direct replacement for a wide array of other GM vehicles and interchanges with part numbers such as 24252114, 24234503, 24230461, and 24242391, among others.
Frequently Asked Questions
What does ‘VIN Programmed’ mean for me?
It means the module arrives ready to install without any additional programming. We load your vehicle’s specific software onto the TCM using your VIN, ensuring it communicates perfectly with your HHR’s other computers for optimal performance and compatibility right out of the box.
Will this HHR Transmission Control Module fix a P0700 code?
A P0700 is a generic code indicating the TCM has detected a fault. While this module often resolves the root cause of that code (such as internal TCM failure or solenoid circuit faults originating in the module), it’s essential to diagnose any other codes that are present alongside the P0700 to confirm the TCM is the source of the issue.
Is this part difficult to install myself?
For most individuals with basic mechanical skills and tools, this is a straightforward installation. The module is easily accessible in the HHR’s engine bay. The entire process typically takes less than 30 minutes. The key is to disconnect the battery first and clear any codes after installation.
Do I need to return my old TCM?
No, there is no core charge for this part. You can keep your old module or dispose of it without the hassle of returning it, saving you time and money on core deposits and return shipping.
How do I know if the TCM is bad and not the transmission itself?
While symptoms can overlap, TCM failure is often characterized by electrical issues, communication faults with a scan tool, and multiple, seemingly unrelated solenoid codes. If the transmission fluid is clean and at the correct level, and the shifting problems are intermittent or electronic in nature, the TCM is a very likely cause.