Is Your Chevy Cobalt or HHR Running Rough?
If you’re dealing with a persistent check engine light, unexplained stalling, poor fuel economy, or a no-start condition in your 2005-2006 Chevrolet Cobalt, HHR, or Pontiac Pursuit, the root cause is often the vehicle’s main computer. The Powertrain Control Module (PCM), also known as the Engine Control Module (ECM), is the central command center for your engine’s performance and efficiency. When it fails, it can create a cascade of frustrating and difficult-to-diagnose problems. Don’t continue swapping sensors and parts hoping for a fix. This is the direct, reliable solution to restore your vehicle’s factory performance.
The Brain of Your Engine: Restored and Ready
This isn’t just a replacement part; it’s a complete, plug-and-play solution. We are providing a genuine GM engine computer, service number 12599714 (compatible with 12600883 and others), that has been meticulously tested and programmed specifically for your vehicle. Using the Vehicle Identification Number (VIN) you provide at checkout, we flash the module with the latest, most stable software updates directly from General Motors. This critical step ensures that the PCM communicates perfectly with your car’s engine, transmission, and other electronic systems, eliminating the need for an expensive trip to the dealership for programming.
From the Diagnostic Bay
We recently had a 2006 Chevy HHR in the shop with a classic case of PCM failure that had the owner chasing his tail for weeks. The car would intermittently lose power and the transmission would shift erratically. The owner had already replaced the throttle body and a speed sensor based on generic trouble codes, with no improvement. When we connected our professional diagnostic tool, we saw communication errors between the PCM and several other modules. The data stream was inconsistent, pointing not to a faulty sensor, but to a faulty processor. We installed one of our VIN-programmed PCMs, performed the quick security relearn procedure, and the HHR ran like new. It’s a textbook example of how a failing computer can mimic other component failures, making a direct replacement 2005-2006 Cobalt PCM the only real fix.
Common Symptoms of a Failing 2005-2006 Cobalt PCM
- ✔ Persistent Check Engine Light (CEL) that won’t clear.
- ✔ Engine stalling or cutting out while driving.
- ✔ Rough or erratic idling.
- ✔ Noticeable decrease in fuel mileage.
- ✔ Harsh or incorrect transmission shifting.
- ✔ Vehicle refuses to start, even with a good battery and starter.
- ✔ Communication error codes (U-codes) stored in the system.
- ✔ Failure to pass state emissions testing.
Guaranteed Compatibility and Simple Installation
This module is a direct fit for a range of GM vehicles and is compatible with numerous service numbers, ensuring you get the correct part. Please verify your vehicle’s fitment below.
This part is compatible with the following GM service numbers: 12599714, 12589998, 12597329, 12600882, 12600883, 12605766, 12605765.
Vehicle Fitment:
- 2005 Chevrolet Cobalt: Electronic Control Module; (LH front engine compartment), ID 12589998
- 2006 Chevrolet Cobalt: Electronic Control Module; (LH front engine compartment), 2.2L (VIN F, 8th digit)
- 2006 Chevrolet HHR: Electronic Control Module; (LH rear engine compartment), 2.2L
- 2005 Pontiac Pursuit: Electronic Control Module; (LH front engine compartment), ID 12589998
- 2006 Pontiac Pursuit: Electronic Control Module; (LH front engine compartment), 2.2L
Installation is straightforward for a DIY mechanic. The module is typically located in the left-hand (driver’s side) engine compartment. After disconnecting the battery, simply unplug the wiring harnesses from the old unit, unbolt it, and install the new one. Once installed, you will need to perform a simple security relearn procedure (often called a CASE relearn or Passlock relearn), which can be done without any special tools and takes about 30 minutes. Instructions for this procedure are widely available online or in your vehicle’s service manual. This final step syncs the new 2005-2006 Cobalt PCM with your vehicle’s anti-theft system.
Frequently Asked Questions
Why do you need my vehicle’s VIN?
Your Vehicle Identification Number (VIN) is essential because it allows us to program the PCM with the exact software and calibrations your car had when it left the factory. This includes details about your engine, transmission, tire size, and other options. This VIN-specific programming makes the installation process as simple as possible.
Is this module difficult to install?
For someone with basic mechanical skills, the physical installation is not difficult. It involves disconnecting the battery, unplugging a few connectors, and removing a few bolts. The most important step after installation is the security relearn procedure, which is a sequence of key turns that you can perform yourself without any special tools.
Will I need to have this programmed by a dealer after I receive it?
No. The unit arrives pre-programmed to your VIN and is ready for installation. The only additional step required is the security relearn, which syncs the module to your car’s anti-theft system. This saves you the time and expense of a dealership visit.
How can I be sure my original PCM is the problem?
While the symptoms listed above are strong indicators, a definitive diagnosis is best. Common signs include multiple unrelated error codes, communication errors with a scan tool, or having ruled out all other possible causes (like sensors or wiring). If your mechanic has diagnosed a faulty PCM, this is the correct replacement part.
Is this a used part?
This is a high-quality, fully tested, and inspected original equipment (OE) part that has been prepared for its next service life. Each unit undergoes rigorous testing to ensure it meets or exceeds factory specifications before being programmed and shipped.