1.1.7 Typing in Business Information
Typing in the repair shop information, which will be shown in the diagnostic report.
2 General information
2.1 On-Board Diagnostics (OBD) II
The first generation of On-Board Diagnostics (OBD I) was developed by the California
Air Resources Board (ARB) and implemented in 1996 to monitor some of the emission
control components on vehicles. As technology evolved and the desire to improve the
OnBoard Diagnostic system increased, a new generation of On-Board Diagnostic system
was developed. This second generation of OnBoard Diagnostic regulations is called "OBD
II". The OBDII system is designed to monitor emission control systems and key engine
components by performing either continuous or periodic tests of specifi c components
and vehicle conditions. When a problem is detected, the OBDII system turns on a warning
lamp (MIL) on the vehicle instrument panel to alert the driver typically by the phrase of
"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 theproblem.
Here below follow three pieces of such valuable information:
1) Whether the Malfunction Indicator Light (MIL) is commanded 'on' or 'off ';
2) Which, if any, Diagnostic Trouble Codes (DTCs) are stored;
3) Readiness Monitor status.
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 is intended to provide you with a guide as to where a fault
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might be occurring within a vehicle. OBDII Diagnostic Trouble Codes consist of a fi vedigit
alphanumeric code. The first character, a letter, identifi es which control system sets the
code. The second character, a number, 0-3; other three characters, a hex character, 0-9
or A-F provide additional information on where the DTC originated and the operating
conditions that caused it to set. Here below is an example to illustrate the structure of the
digits:
DTC Example
P0201
ldentifies what section of the
system is malfunctioning
Systems
P=Powertrai
B=Body
C=Chassis
Identifies the system where the
U=Network
problem is located."P"Code systems
are listed below."B","C"and"U"Code
system will vary.
0 - Fuel and air metering; Auxiliary
Code Type
emlssion controls
0 - Generic(SAE)
1 - Fuel and air metering
1 - Manufacturer Specific
2 - Fuel and air metering (injector
2 - Generic ('P"Codes) and
circuit malfunction only)
Manufacturer
3 - Ignition system or misfire
Specific ("B","C"and
4 - Auxiliary emission control system
"U"Codes)
5 - Vehicle speed control and idl
3 - Includes both Generic
control system
and Manufacturer
6 - Computer output circuits
Specific Codes
7 - Transmission
8 - Transmission
9 - Transmission
A - Hybrid Propulsion
B - Hybrid Propulsion
C - Hybrid Propulsion
Sub-systems
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