Is Your 2006 Trailblazer Running Rough? The Solution is Here.
If you’re dealing with a persistent check engine light, erratic engine behavior, or frustrating no-start conditions, the heart of the problem may lie with a failing Powertrain Control Module (PCM). As the central computer for your vehicle’s engine and transmission, its proper function is critical for performance, fuel economy, and reliability. This direct-fit replacement PCM, part number 12606373, is the definitive solution to get your 2006 Chevrolet Trailblazer, GMC Envoy, or other compatible GM vehicle running like new again.
We take the guesswork and hassle out of the replacement process. Unlike a generic module from a parts store or a salvage yard unit with an unknown history, this PCM arrives at your door pre-programmed specifically for your vehicle. Using the Vehicle Identification Number (VIN) you provide, we flash the module with the latest, most stable software updates directly from GM. This ensures perfect compatibility with your vehicle’s specific options and systems, leading to a smoother installation and immediate performance restoration.
From the Diagnostic Bay
I remember a 2006 Envoy 4.2L that came into the shop with a bizarre set of symptoms. The owner complained of intermittent stalling at stoplights and a transmission that would randomly refuse to shift out of second gear. We checked everything – sensors, wiring, fluid levels – and found nothing obviously wrong. No consistent trouble codes were stored, just a few random communication errors. After hours of chasing ghosts, we decided to inspect the PCM. We found subtle corrosion on one of the connector pins that was causing intermittent signal loss. We swapped in a VIN-programmed module, performed the security relearn, and the truck ran perfectly. It’s a powerful reminder that when everything else checks out, the brain of the operation is often the culprit.
Symptoms of a Failing Powertrain Control Module
- ✔ Persistent Check Engine Light (CEL) with various trouble codes, especially communication or internal processor codes (e.g., P0601, P0606).
- ✔ Engine stumbling, misfiring, or running rough.
- ✔ Unexplained decrease in fuel economy.
- ✔ Harsh or erratic automatic transmission shifting.
- ✔ Intermittent or complete no-start condition where the engine cranks but won’t fire.
- ✔ Stalling for no apparent reason, either while driving or at idle.
- ✔ Failure to pass an emissions test due to module-related faults.
Why Our Pre-Programmed 2006 Trailblazer Powertrain Control Module is the Superior Choice
Choosing the right replacement part is crucial. Our process is designed to provide a reliable, long-term solution. When you order this 2006 Trailblazer Powertrain Control Module, you are not just getting a part; you are getting a comprehensive service. We handle the complex programming, saving you a costly trip to the dealership and the specialized tools required. The module is loaded with factory-correct software that manages critical functions like fuel mixture, ignition timing, transmission shift points, and emissions controls, restoring the precise performance your vehicle was designed to deliver.
Guaranteed Compatibility and Fitment
This module is a direct replacement for a wide range of GM mid-size trucks and SUVs. Please verify your original part number against the list below to ensure compatibility. This unit replaces the following part numbers:
12569773, 12588650, 12589311, 12589585, 12591647, 12591648, 12593531, 12593532, 12594430, 12594431, 12596783, 12596784, 12597521, 12597776, 12597777, 12600818, 12604438, 12604439, 12606369, 12606373, 12606374, 12606398, 12606399, 19209820, 19209821
This part is confirmed to fit:
- 2006 Buick Rainier (4.2L)
- 2004-2006 Chevrolet Colorado
- 2006 Chevrolet Trailblazer & Trailblazer EXT (4.2L)
- 2004-2006 GMC Canyon
- 2006 GMC Envoy & Envoy XL (4.2L)
- 2006 Hummer H3
- 2006 Isuzu Ascender (4.2L)
- 2006 Isuzu i-280 & i-350
- 2006 Saab 9-7x (6 cylinder)
Installation Guide
While professional installation is always recommended, replacing the PCM is a straightforward process for a skilled DIY mechanic. The key is to perform the security relearn procedure after installation.
- Disconnect the Battery: Always disconnect the negative battery terminal before working on any electronic components.
- Locate the PCM: On the 2006 Trailblazer/Envoy platform with the 4.2L engine, the PCM is located on the driver’s side of the engine block, below the intake manifold. On Colorado/Canyon/H3 models, it is typically on the RH firewall.
- Disconnect Connectors: Carefully release the locking tabs and disconnect the wiring harness connectors from the old module.
- Swap the Modules: Unbolt the old PCM from its bracket and install the new one in its place.
- Reconnect Everything: Securely plug the wiring harnesses into the new module and reconnect the negative battery terminal.
- Perform Security Relearn: You will need to perform a security relearn procedure so the new PCM can communicate with your vehicle’s anti-theft system. This typically involves a sequence of turning the key on and off and can be found in your vehicle’s service manual or online. A CASE (Crankshaft Angle Sensor Error) relearn may also be required, which necessitates a bi-directional scan tool.
Frequently Asked Questions
What is a PCM and what does it do?
The Powertrain Control Module (PCM) is your vehicle’s main computer. It controls all aspects of engine and transmission function, including fuel injection, spark timing, idle speed, and transmission shifting, to ensure optimal performance, fuel efficiency, and low emissions.
Do I need to program this module?
No. This is the biggest benefit of our service. We program the module for you using your vehicle’s VIN before we ship it. This saves you a trip to the dealership and ensures it works correctly with your specific vehicle configuration right out of the box.
What is a “CASE Relearn” and will I need to do one?
A CASE (Crankshaft Angle Sensor Error) Relearn is a procedure that synchronizes the new PCM with the crankshaft position sensor. While the vehicle will often run without it, performing this procedure with a capable scan tool is highly recommended to prevent a P1336 trouble code and ensure accurate misfire detection.
How do I find my vehicle’s VIN?
Your 17-digit VIN can be found on your vehicle’s registration, insurance card, or on the vehicle itself. Look for a small metal plate on the driver’s side of the dashboard visible through the windshield, or on the sticker inside the driver’s side door jamb.
Will this fix my transmission shifting problems?
In many cases, yes. The PCM is responsible for controlling the transmission’s shift solenoids and interpreting data from speed sensors. If your shifting issues are electronic in nature and caused by a faulty module, this replacement part is the correct fix. It will not solve mechanical issues within the transmission itself.