Diagnostic trouble codes or DTC are identification codes that trigger when something is wrong within a vehicle. These codes can be accessed via the vehicles computer, or the OBDII port. The OBDII port is the access site of where the plug and play, or PNP, units plug into and track. Since the PNP units operate off of the same computer the DTC codes do, it only makes sense that PNP can record DTC information.
DTC with PNP
Within the DTC codes, the first number specifies whether it’s a generic code or specific to that vehicle type. The final three numbers within the code indicate what’s wrong within the vehicle. For example, P0420 indicates Catalyst System Efficiency Below Threshold Bank 1. While this information is helpful in determining why the check engine light is on, the average person doesn’t know what that means in regards to their vehicle. When using a PNP tracking unit, the DTC code, description and detailed description can help the average vehicle owner determine what needs to be completed.