How the Diagnostic Trouble Code is created:
A DTC is made up of 5 digits.
The chart below shows the composition of a DTC. With this information you can easily determine what system to trouble shoot without knowing the exact description of the code.
There are two categories of DTC’s that apply to OBDII.
Type A:
1.Emissions related.
2.Requests illumination of the MIL after one failed driving cycle.
3.Stores a freeze frame DTC after one failed driving cycle.
Type B:
1.Emissions related.
2.Sets a Pending Trouble Code after one failed driving cycle.
3.Clears a Pending Trouble Code after one successful driving cycle.
4.Turns on the MIL after two consecutive failed driving cycles.
5.Stores a freeze frame after two consecutive failed driving cycles.