Is Your Chevy HHR’s Transmission Acting Unpredictable?
If you’re dealing with the frustration of a 2006-2011 Chevy HHR that slams into gear, refuses to shift, or has its check engine light glaring at you, the culprit is very often a faulty Transmission Control Module (TCM). As the electronic brain of your automatic transmission, a failing TCM can turn a reliable daily driver into a source of constant stress. Symptoms can start small—a slight hesitation—and quickly escalate to your vehicle being stuck in ‘limp mode,’ making it unsafe and unreliable. This isn’t just an inconvenience; it’s a critical failure that impacts performance, fuel economy, and your peace of mind.
This is where our pre-programmed T42 TCM, service number 24234503, comes in. It’s the definitive, no-hassle solution designed to restore your vehicle’s shifting logic and get you back on the road with confidence. We take the guesswork and expensive dealership trips out of the equation. By programming the module to your HHR’s specific Vehicle Identification Number (VIN) before it ships, we deliver a true plug-and-play component. It arrives ready for installation, loaded with the latest GM software updates to ensure perfect communication between your engine and transmission.
Case Study: A Tricky Diagnosis
I remember a 2009 HHR that came into my shop with a persistent P0700 code and what the owner described as ‘violent shifting.’ They had already replaced two shift solenoids with no improvement. After a quick data scan, I saw erratic pressure readings that didn’t match the commanded states. This is a classic sign that the TCM itself is the problem, not the mechanical parts it controls. We installed one of our VIN-programmed modules, and in less than an hour, the car was shifting like it just left the factory. The customer saved hundreds by avoiding further incorrect diagnoses and a costly trip to the dealer for programming.
Is Your HHR Showing These Telltale Signs?
A failing TCM will give you clear warnings. If you’re experiencing any of the following, it’s time to consider a replacement:
- ✔ Harsh, jerky, or delayed gear shifts.
- ✔ Vehicle is stuck in one gear (often 2nd or 3rd, known as limp mode).
- ✔ Check Engine Light or Transmission Warning Light is illuminated.
- ✔ Diagnostic Trouble Codes (DTCs) are present, such as P0700, P0750, P0753, or other solenoid-related faults.
- ✔ The transmission refuses to upshift or downshift properly.
- ✔ A noticeable drop in fuel efficiency.
- ✔ Intermittent loss of communication with the TCM on a scan tool.
A Straightforward Guide to Your 2006-2011 HHR Transmission Control Module Installation
One of the best parts about this fix is how accessible it is for the average DIYer. You don’t need a vehicle lift or specialized transmission tools. The entire process should take less than 30 minutes.
- Safety First: Disconnect the negative terminal from your vehicle’s battery to prevent any electrical shorts and to help reset the vehicle’s computer systems.
- Locate the TCM: On the 2006-2011 Chevrolet HHR, the Transmission Control Module is typically found in the engine compartment, mounted to the left-hand (driver’s side) inner fender or strut tower area.
- Disconnect and Remove: Carefully unplug the electrical connectors from the old module. Press the release tabs firmly to avoid breaking them. Then, unbolt the module from its mounting bracket.
- Install the New Module: Bolt the new, pre-programmed TCM into place. Reconnect the electrical connectors, ensuring they click securely into position.
- Final Steps: Reconnect the negative battery terminal. While the module is plug-and-play, it’s always good practice to use a basic OBD2 scan tool to clear any stored fault codes from the previous failure. Start the vehicle and take it for a test drive to confirm smooth shifting.
Verified Fitment for Your Vehicle
This T42 TCM is a direct-fit replacement for the following vehicles, among others. Please verify your part number (24234503) or contact us with your VIN to ensure compatibility.
- Chevrolet HHR (2006-2011): Transmission; (LH engine compartment)
- Chevrolet Cobalt (2006-2010): Transmission; (LH strut tower)
- Pontiac G5/G6 (2006-2010): Transmission; (LH strut tower)
- Saturn Ion (2006-2007): Transmission; (behind LH strut tower)
- Chevrolet Malibu (2006-2010): Transmission; (LH frame rail)
Frequently Asked Questions
Do I need to take this part to a dealer for programming?
No. This Transmission Control Module is delivered to you pre-programmed to your vehicle’s VIN. It is ready for installation right out of the box, saving you time and money.
What is the warranty on this TCM?
This part comes with a one-year, unlimited mileage warranty, giving you confidence in the quality and durability of your repair.
Is this compatible with other part numbers?
Yes, this module is interchangeable with a wide range of GM service numbers, including 24252114, 24230461, 24234274, 24239224, and more. If your part number is on the list, this is the correct replacement.
Will this fix a P0700 trouble code?
A P0700 code is a general transmission fault request from the TCM to the ECM to turn on the check engine light. While a faulty TCM is a very common cause, this code can also be triggered by other transmission issues. However, if you are also experiencing erratic shifting or other symptoms listed, replacing the TCM is the most likely solution.
Is there a core charge?
No, there is no core charge for this module. You can keep your old part without any hassle or need to return it.