Understanding your Chevy Blazer’s OBD2 codes can be crucial for diagnosing and resolving car issues efficiently. While using a diagnostic scan tool is generally recommended for reading Diagnostic Trouble Codes (DTCs), there’s an alternative method that can be used on certain vehicles, potentially including your Chevy Blazer. This guide will walk you through how to access these codes using your vehicle’s Data Link Connector (DLC).
Your Chevy Blazer, like many modern vehicles, is equipped with a 16-pin Data Link Connector (DLC), which is a standardized interface used to access the vehicle’s On-Board Diagnostics II (OBD2) system. This system monitors various aspects of your car’s performance and can detect malfunctions, storing them as DTCs. Typically, you would use an OBD2 scanner to retrieve these codes. However, in situations where a scanner isn’t available, you might be able to flash these codes using the DLC and your Blazer’s Powertrain Control Module (PCM).
To attempt this method, you’ll need to locate the DLC connector in your Chevy Blazer. It’s commonly found under the dashboard on the driver’s side. Once located, identify terminal “6” on the DLC – this is the diagnostic terminal and is usually the third terminal from the left on the top row. You’ll also need to find terminal “5”, which is the internal PCM ground and is located directly to the left of terminal “6” on the same top row.
To initiate the code flashing process, you need to ground terminal “6” by connecting it to terminal “5”. You can use a jumper wire or a paper clip to carefully connect these two terminals. After connecting terminals “5” and “6”, turn your Chevy Blazer’s ignition switch to the “ON” position, but do not start the engine.
At this point, the Malfunction Indicator Lamp (MIL), often known as the “Service Engine Soon” light or “Check Engine Light,” should begin to flash. It should first flash Diagnostic Trouble Code (DTC) 12 three times consecutively. DTC 12 is a system check code, indicating that the diagnostic system is functioning correctly. This will appear as a sequence of flashes: “flash, pause, flash-flash, long pause, flash, pause, flash-flash, long pause, flash, pause, flash-flash.” If you do not see DTC 12, it suggests a problem within the diagnostic system itself, and further professional diagnosis might be necessary.
Following the DTC 12 output, if any other diagnostic trouble codes are stored in your Chevy Blazer’s memory, the MIL will then flash these codes. Each DTC will be indicated three times. If multiple DTCs are present, they will be displayed in numerical order, from the lowest to the highest. If no other DTCs are stored, the system will continue to output DTC 12.
While this method can provide a basic way to retrieve OBD2 codes for your Chevy Blazer without a scan tool, it’s important to remember that modern OBD2 scanners offer much more detailed information and capabilities. For comprehensive diagnostics and efficient troubleshooting, especially for complex issues, using a dedicated OBD2 scanner is always the recommended approach. This flashing method serves as a basic alternative when a scanner is not readily available, allowing you to get a preliminary understanding of potential problems indicated by your Chevy Blazer’s OBD2 system.
