DTC (fault codes)
Diagnostic Trouble Code
The diagnostic codes a car logs when something is off. A scanner reads them; each code points to a system, from the battery to a door left open.
A DTC (diagnostic trouble code) is how the car's computer logs an anomaly. Each code is a standardized tag that flags which system reported the problem and what kind it is.
Not all carry the same weight: some flag a serious fault, others are minor or transient warnings. On an EV, the codes tied to the battery and high-voltage system are the ones most worth watching. A scan shows them raw; the value is in interpreting them and separating noise from what matters.