DTC Format
- Diagnostic Trouble Code (SAE J2012)
- DTCs used in OBD-II vehicles begin with a letter followed by a four-digit number.
The letter of the beginning of the DTC identifies the function of the monitored device that has failed. A "P" indicates a powertrain device, "C" indicates a chassis device. "B" is for body device and "U" indicates a network or data link code. The first number indicates if the code is generic (common to all manufacturers) or manufacturer-specific. A "0" & "2" indicates generic, "1" indicates manufacturer-specific. The second number, ranging from 1 to 7, indicates the affected system.
The following is a list showing what numbers are assigned to each system.
- Fuel and air metering
- Fuel and air metering (injector circuit malfunction only)
- Ignition system or misfire
- Auxiliary emission controls
- Vehicle speed controls and idle control system
- Computer output circuits
- Transmission
The last two numbers of the DTC indicates the component or section of the system where the fault is located.