Diagnostic Trouble Codes for OBD II and Details
Breakdown of an OBDII (DTC) Diagnostic Trouble Code
First digit structure is as follows:
Pxxxx for powertrain
Bxxxx for body
Cxxxx for chassis
Uxxxx for class 2 network
Second digit structure is:
P0xxx Government required codes
P1xxx Manufacturer codes for additional emission system function; not required but reported to the government
Third digit structure is:
Px1xx measurement of air and fuel
Px2xx measurement of air and fuel
Px3xx ignition system
Px4xx additional emission control
Px5xx speed and idle regulation
Px6xx computer and output signals
Px9xx control modules, input and output signals
Fourth and fith digit:
Fault (00 to 99)
Types of DTC’s
There are two categories of DTC’s that apply to OBD II. They are listed below with Type A being the more severe.
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.
I. 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.