Is Your Chevrolet HHR Running Rough? The PCM Might Be the Culprit.
The Powertrain Control Module, or PCM, is the central command center of your 2007-2011 Chevrolet HHR. It’s a sophisticated computer that manages everything from fuel injection and ignition timing to transmission shifting and emissions control. When it begins to fail, it can cause a cascade of confusing and frustrating problems that can leave your vehicle unreliable or even undrivable. If you’re dealing with persistent check engine lights, poor fuel economy, or erratic engine behavior, you’ve come to the right place for a dependable solution.
This is a direct replacement Powertrain Control Module for your vehicle, service number 12629019 (interchangeable with 12597125, 12612397, 12594750, and others). We take the guesswork out of the repair by pre-programming the unit specifically for your vehicle using your VIN. This ensures that it has the latest software updates from GM and is ready for installation right out of the box, restoring your vehicle’s original performance and reliability.
From the Diagnostic Bay
We had a 2009 HHR come into the shop with a complaint of intermittent stalling and a check engine light that would come and go. The owner had already replaced the spark plugs, ignition coils, and even the mass airflow sensor with no success. The codes were all over the place—misfires, communication errors, and O2 sensor faults. After hours of chasing wires and testing sensors, we hooked up our scope to the PCM’s main connectors. We found that the 5-volt reference signal, which powers many of the engine’s key sensors, was dropping out randomly. This wasn’t a sensor or wiring issue; the PCM itself was failing internally. We installed a VIN-programmed module just like this one, performed the security relearn, and the HHR ran perfectly. It’s a classic example of how a failing PCM can mimic a dozen other problems, making a quality, correctly programmed replacement essential.
Diagnosing a Faulty 2007-2011 HHR PCM
A failing engine computer can manifest in numerous ways, often mimicking other component failures. If your HHR is exhibiting several of the following symptoms, it’s a strong indicator that the PCM is the root cause of your issues. Verifying these symptoms can help you make an accurate diagnosis and avoid replacing unnecessary parts.
Common Symptoms of PCM Failure
- ✔ Check Engine Light: The check engine light is illuminated, often with communication-related trouble codes (U-codes) or multiple, seemingly unrelated sensor codes.
- ✔ No-Start or Hard Starting: The engine cranks but refuses to start, or takes an unusually long time to fire up, either hot or cold.
- ✔ Poor Engine Performance: You may experience a significant loss of power, hesitation during acceleration, or rough idling.
- ✔ Erratic Shifting: The automatic transmission may shift harshly, get stuck in a gear, or shift at the wrong times.
- ✔ Reduced Fuel Economy: A sudden and unexplained drop in your vehicle’s MPG is a common sign that the air/fuel mixture is not being managed correctly.
- ✔ Stalling: The engine may stall unexpectedly while driving or when coming to a stop.
- ✔ Failed Emissions Test: The vehicle is unable to pass a smog or emissions inspection due to PCM-related faults.
Your Plug-and-Play Solution
Our process is designed to be simple and effective. When you purchase this module, you provide us with your vehicle’s VIN. Our technicians then access the most current GM calibration files for your specific vehicle and flash the module. This ensures all factory settings and operational parameters are perfectly matched to your HHR’s engine, transmission, and options. This critical step eliminates the need for an expensive trip to the dealership for programming, saving you time and money. This module is a direct fit for a wide range of GM vehicles, including the Chevy Cobalt, Malibu, Pontiac G5, G6, Saturn Aura, and various trucks and vans. Please check the fitment list to confirm compatibility.
Frequently Asked Questions
What information do you need from me?
After you place your order, we will need the 17-digit Vehicle Identification Number (VIN) from your vehicle. This is typically found on your driver’s side dashboard (visible through the windshield) or on the driver’s side door jamb sticker.
Is this part difficult to install?
The physical installation is straightforward for a DIY mechanic. On the HHR, the PCM is located in the left rear of the engine compartment. It involves disconnecting the battery, unplugging the electrical connectors, and unbolting the module. The most important step after installation is performing the security relearn procedure.
What is a security relearn procedure?
This is a simple procedure that syncs the new PCM with your vehicle’s anti-theft system. It typically involves turning the key to the ‘ON’ position for 10-15 minutes, then off, and repeating this cycle three times. We include instructions for this process with your order. No special tools are required.
Is this a new or used part?
This is a high-quality, tested, and guaranteed functional replacement part. Each unit is meticulously inspected and programmed with the latest GM software to ensure it meets or exceeds original equipment performance.
Will this fix my check engine light?
If the check engine light and other symptoms are caused by a faulty PCM, this replacement module will resolve the issue. It is crucial to ensure your vehicle’s problem has been properly diagnosed before ordering, as this part will not fix issues caused by other faulty sensors or wiring.