Is Your Chevrolet HHR Shifting Erratically or Stuck in Gear?
If you’re experiencing frustrating and unpredictable transmission behavior in your 2006-2011 Chevrolet HHR, a failing Transmission Control Module (TCM) is the most likely culprit. Symptoms like harsh gear changes, delayed engagement from park to drive, or the dreaded “limp mode” can make your vehicle unreliable and unsafe. This T42 TCM, service part number 24243921, is the definitive solution, arriving pre-programmed to your vehicle’s specific VIN for a seamless, plug-and-play installation.
From the Diagnostic Bay
We recently had a 2009 HHR come into the shop with the check engine light on and the transmission stuck in 3rd gear. The owner had already been quoted over $2,500 for a complete transmission rebuild at another shop. After a quick scan, we pulled code P0700 (Transmission Control System Malfunction) and several solenoid-specific codes. Instead of jumping to the worst-case scenario, we inspected the TCM. After installing one of our VIN-programmed T42 modules, we cleared the codes, and the car shifted perfectly. The customer saved thousands of dollars by correctly diagnosing the electronic failure instead of assuming a major mechanical one. This is a classic case where the “brain” fails, not the body.
Diagnosing a Faulty HHR Transmission Module
The TCM is the central computer for your automatic transmission, responsible for interpreting data from various sensors to control shift solenoids, regulate hydraulic pressure, and manage torque converter clutch lockup. When it begins to fail, it can cause a wide range of issues that mimic internal transmission damage. Before condemning your transmission, check for these common signs of a bad TCM.
Symptoms of a Failing T42 TCM
- ✔ Harsh or Erratic Shifting: Your HHR may slam into gear, hesitate between shifts, or shift at incorrect RPMs.
- ✔ Stuck in Limp Mode: The transmission may default to a single gear (usually 2nd or 3rd) to prevent further damage, severely limiting vehicle speed.
- ✔ Check Engine & Transmission Warning Lights: The illumination of the check engine light, often accompanied by a transmission-specific warning, is a key indicator. Common diagnostic trouble codes (DTCs) include P0700, P0750, P0753, P0758, and other solenoid-related faults.
- ✔ No Upshift or Downshift: The vehicle may refuse to shift into higher gears or fail to downshift when you slow down, leading to poor acceleration and engine lugging.
- ✔ Poor Fuel Economy: Inefficient shifting and incorrect torque converter lockup caused by a faulty module can lead to a noticeable decrease in MPG.
- ✔ False Overheating Signals: The TCM might incorrectly report that the transmission is overheating, even when temperatures are normal.
The Plug-and-Play Solution: VIN Programming Included
Dealerships and many other suppliers will sell you a blank module that requires expensive and complicated programming with specialized tools. Our T42 TCMs eliminate this step entirely. We use your vehicle’s VIN to flash the module with the latest GM software updates specific to your HHR. This ensures perfect communication between the TCM, the Engine Control Module (ECM), and other vehicle systems right out of the box. This critical step guarantees optimal shift patterns, fuel efficiency, and resolves common electronic faults without any additional programming fees or trips to the dealer.
This module is a direct replacement for a wide range of original equipment part numbers, including 24252114, 24234503, 24230461, 24234274, 24243921, and more, making it a versatile solution for many GM vehicles from 2006-2014 equipped with 4-speed automatic transmissions like the 4L60E and 4L65E.
Installation is Simple
Replacing the HHR Transmission Module is a straightforward job that can be completed in under 30 minutes with basic hand tools. On the 2006-2011 HHR, the TCM is typically located in the left-hand (driver’s side) engine compartment, often near the strut tower. Simply disconnect the negative battery terminal, unplug the electrical connectors from the old module, unbolt it, and install the new one in its place. Reconnect everything, and you’re ready to go. Using a basic OBD2 scanner to clear any stored fault codes after installation is recommended.
Don’t let a faulty TCM keep your HHR off the road. This VIN-programmed T42 module is the most reliable and cost-effective way to restore your vehicle’s performance and driveability. Order today and experience the difference of a transmission that shifts like new.
Frequently Asked Questions
Why is VIN programming so important for this module?
VIN programming loads your vehicle’s specific calibration files onto the TCM. This ensures it communicates correctly with the engine computer and other systems, controlling shift points, line pressure, and torque converter lockup exactly as the manufacturer intended for your HHR’s specific configuration. A non-programmed module will not function correctly and can cause further issues.
Is this part difficult to install on my 2008 Chevy HHR?
No, installation is straightforward for someone with basic mechanical skills. The HHR Transmission Module is located in the driver’s side engine compartment. The process involves disconnecting the battery, unplugging two electrical connectors, removing a few mounting bolts, and swapping the unit. The entire job typically takes less than 30 minutes.
Will this fix a P0700 transmission code?
A P0700 code is a general fault code indicating that the TCM has detected a problem and has requested the check engine light to be turned on. While this module often resolves the root cause (like internal TCM failure or faulty solenoid drivers), you should have the specific transmission codes read to confirm the diagnosis. This part directly fixes issues originating from the module itself.
Do I need to return my old part? Is there a core charge?
No, there is absolutely no core charge for this part. You can keep your old module, recycle it, or dispose of it at your convenience without any additional fees or hassle.
Is this an OEM General Motors part?
This is an OEM-quality part built to the original manufacturer’s specifications and standards. It is designed to meet or exceed the performance and reliability of the original factory module, and it comes with a one-year warranty for your peace of mind.