Diagnostic Trouble Codes for OBD II 


Anatomy of OBDII (DTC) Diagnostic Trouble Code

A DTC is made up of 5 digits. The figure below demonstrates the composition of a DTC. With this information it is easier to trouble shoot DTC without knowing the description of the code.

 

Example    P0101

1st digit    B-Body, C-Chassis, P-Powertrain, U-Network

2nd digit   0-SAE, 1 mfg

3rd digit    1 Air & Fuel Metering
                2 Air & Fuel Metering  (Injector Circuit)
                3 Ignition System or Misfire
                4 Auxiliary Emissions Controls
                5 Vehicle Speed Controls And Idle Control System
                6 Computer Output Circuit
                7 Transmission
                8 Transmission

4th & 5th digit  - two place fault code 0-99

 

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.

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
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.
Stores a freeze frame after two consecutive failed driving cycles.

DTC Codes - P0100-P0199 – Fuel and Air Metering

DTC Codes - P0200-P0299 – Fuel and Air Metering (Injector Circuit)

DTC Codes - P0300-P0399 – Ignition System or Misfire

DTC Codes - P0400-P0499 – Auxiliary Emissions Controls

DTC Codes - P0500-P0599 – Vehicle Speed Controls and Idle Control System

DTC Codes - P0600-P0699 – Computer Output Circuit

DTC Codes - P0700-P0799 – Transmission

DTC Codes - P0800-P0899 – Transmission