Is Your Chevrolet HHR Shifting Erratically?
If you’re experiencing frustrating and unpredictable transmission behavior in your 2006-2011 Chevrolet HHR, a faulty Transmission Control Module (TCM) is the most likely culprit. This critical component acts as the brain of your automatic transmission, controlling shift points, torque converter lockup, and line pressure. When it fails, it can lead to a host of problems that make your vehicle unreliable and unsafe to drive. This genuine GM T42 Transmission Control Module, service part number 24255280, is the definitive solution to restore your vehicle’s performance and peace of mind.
From the Diagnostic Bay
We recently had a 2009 HHR come into the shop with classic symptoms of a failing transmission. The owner had already spent a significant amount of money replacing shift solenoids based on a generic code reader’s output, but the harsh 1-2 shift and intermittent ‘limp mode’ persisted. After a quick scan with our professional equipment, we identified communication errors pointing directly to the TCM. Instead of a costly transmission rebuild, the fix was this pre-programmed 2006-2011 HHR TCM. The customer was back on the road in under an hour with a perfectly shifting vehicle, saving thousands of dollars and a lot of headaches.
Symptoms of a Failing HHR Transmission Control Module
- ✔ Harsh or Delayed Shifting: Experiencing sudden, jerky shifts or a noticeable lag when the transmission changes gears.
- ✔ Stuck in Gear (Limp Mode): The vehicle refuses to shift out of a single gear (often 2nd or 3rd) to prevent further damage.
- ✔ Check Engine Light: The Malfunction Indicator Lamp (MIL) illuminates, often with transmission-specific Diagnostic Trouble Codes (DTCs) like P0700, P0750, or other solenoid-related faults.
- ✔ No Upshift or Downshift: The transmission fails to shift to higher or lower gears as needed, causing poor acceleration and high RPMs.
- ✔ Poor Fuel Economy: Inefficient shifting and torque converter operation lead to a sudden drop in your vehicle’s gas mileage.
- ✔ Erroneous Warning Lights: Transmission temperature warnings or other dash lights may appear without a clear cause.
The Plug-and-Play Solution: VIN Programmed for Your HHR
The biggest challenge when replacing modern electronic modules is the need for expensive dealership programming. We eliminate that step entirely. Before this module ships, we program it with your HHR’s specific Vehicle Identification Number (VIN) and the latest GM software updates. This ensures that it communicates flawlessly with your vehicle’s other systems, like the Engine Control Module (ECM) and Body Control Module (BCM), right out of the box. There’s no need for a trip to the dealer or a special scan tool for setup. It’s a true plug-and-play repair.
Key Features and Benefits
- Direct Fit Replacement: Engineered to meet or exceed original equipment specifications for a perfect fit and function.
- VIN Programming Included: Arrives ready for installation, saving you time and hundreds of dollars in programming fees.
- Restores Performance: Corrects common shifting issues, eliminates transmission-related error codes, and improves overall vehicle drivability.
- No Core Charge: Keep your old part without the hassle of core returns or extra charges.
- One-Year Warranty: Drive with confidence knowing your purchase is protected against defects.
Easy Installation for the 2006-2011 HHR TCM
Replacing the TCM on your Chevy HHR is a straightforward process that can be completed with basic hand tools. The module is conveniently located in the engine compartment on the driver’s side, near the strut tower.
- Safety First: Always disconnect the negative terminal of your vehicle’s battery before starting any electrical work.
- Locate the Module: Find the TCM on the LH (driver’s side) of the engine compartment.
- Disconnect and Remove: Carefully unplug the electrical connectors. Be gentle with the locking tabs. 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 harnesses.
- Final Steps: Reconnect the battery terminal. While the module is plug-and-play, it is best practice to use a standard OBDII scan tool to clear any stored fault codes from the vehicle’s memory. Start the vehicle and take it for a test drive to confirm that all shifting issues are resolved.
Frequently Asked Questions
What is a T42 TCM and what does it do?
The T42 is a specific generation of Transmission Control Module used by General Motors in many of their 4-speed automatic transmissions, like the 4L60E found in your HHR. It’s a dedicated computer that controls all electronic functions of the transmission, ensuring smooth shifting, proper fluid pressure, and optimal fuel efficiency based on data from various vehicle sensors.
Is this part really plug-and-play?
Yes. By providing us with your vehicle’s VIN during checkout, we program the module specifically for your car. This programming ensures it works seamlessly with your engine and other systems upon installation, eliminating the need for any additional programming or setup procedures from a dealership.
Where is the TCM located on a 2006-2011 Chevy HHR?
On the 2006-2011 Chevrolet HHR, the Transmission Control Module is typically found in the engine compartment, mounted on the driver’s side (LH) near the strut tower or under the air cleaner box.
Do I need to return my old TCM?
No. We do not require a core return for this part. You can keep your old module or dispose of it responsibly without any additional core charges or hassle.
What happens if I don’t replace a failing TCM?
Continuing to drive with a faulty TCM can lead to more severe and expensive damage. Poor shifting can cause premature wear on internal transmission components like clutches and bands, potentially leading to a complete transmission failure that requires a full rebuild or replacement.