2. General Information
2.1 On-Board Diagnostics (OBD) II
The first generation of On-Board Diagnostics (called OBD l)
was developed by the California Air Resources Board (CARB)
and implemented in 1988 to monitor some of the emission
control components on vehicles. As technology evolved and
the desire to improve the On-Board Diagnostic system
increased, a new generation of On-Board Diagnostic system
was developed. This second generation of On-Board Diagnos-
tic regulations is called "OBD II".
The OBD II system is designed to monitor emission control
systems and key engine components by performing either
continuous or periodic tests of specific components and
vehicle conditions When a problem is detected, the OBD II
system turns on a warning lamp (MIL) on the vehicle instru-
ment panel to alert the driver typically by the phrase "Check
Engine" or "Service Engine Soon" The system will also store
important information about the detected malfunction so that a
technician can accurately find and fix the problem. Here below
follow three pieces of such valuable Information:
2.2 Diagnostic Trouble Codes (DTCs)
OBD II Diagnostic Trouble Codes are codes that are stored by
the on-board computer diagnostic system in response to a
problem found in the vehicle. These codes identify a particular
problem area and are intended to provide you with a guide as
to where a fault might be occurring within a vehicle. OBD II
Diagnostic Trouble Codes consist of a five-digit alphanumeric
code. The first character, a letter, identifies which control
system sets the code. The other four characters, all numbers,
provide additional information on where the DTC originated
and the operating conditions that caused it to be set. Below is
an example to illustrate the structure of the digits:
2 EN
To Next Page
Loading...
