Vehicle Diagnostic Trouble Codes (DTCs)

What are Diagnostic Trouble Codes (DTCs) in vehicles?

How are DTCs related to the Malfunction Indicator Lamp (MIL) in vehicles?

Diagnostic Trouble Codes (DTCs) in vehicles are codes generated by the onboard diagnostic system to indicate specific issues or malfunctions in the vehicle.

The Malfunction Indicator Lamp (MIL) in vehicles is illuminated when certain emissions-related faults are detected by the onboard diagnostic system.

Diagnostic Trouble Codes (DTCs) are alphanumeric codes that are stored in a vehicle's computer system to indicate specific issues or malfunctions that have been detected by the onboard diagnostic system. These codes help technicians diagnose and repair problems in the vehicle.

Relation to the Malfunction Indicator Lamp (MIL)

The Malfunction Indicator Lamp (MIL), also known as the Check Engine Light, is a warning light on the vehicle's dashboard that illuminates when certain emissions-related faults are detected by the onboard diagnostic system. When the MIL is illuminated, it indicates that there is a problem that needs attention and may affect the vehicle's emissions output. In many cases, the MIL will also be accompanied by one or more DTCs stored in the vehicle's computer system.

It's important to note that not all DTCs will trigger the MIL to illuminate. While emissions-related faults will typically cause the MIL to come on, there can be other non-emissions-related faults stored as DTCs in the vehicle's computer system that do not affect emissions and therefore do not illuminate the MIL.