Onboard Diagnostics
DIAGNOSTIC TROUBLE CODES (DTCs)
cycles as a counter to automatically erase a specific code and related data
from its memory. When no faults related to the original problem are
detected within a specified number of warm-up cycles, the code is erased
automatically.
DIAGNOSTIC TROUBLE CODES (DTCs)
Diagnostic Trouble
Codes (DTCs) are
codes that identify a
specific problem area.
Diagnostic Trouble Codes (DTCs) are meant
to guide you to the proper service procedure
in the vehicle’s service manual. DO NOT
replace parts based only on DTCs without
first consulting the vehicle’s service manual
for proper testing procedures for that
particular system, circuit or component. DTCs
are alphanumeric codes that are used to identify a problem that is
present in any of the systems that are monitored by the on-board
computer (PCM). Each trouble code has an assigned message that
identifies the circuit, component or system area where the problem was
found.
OBD 2 diagnostic trouble codes are made up of five characters:
¾ The 1st character is a letter. It identifies the “main system” where the fault
occurred (Body, Chassis, Powertrain, or Network).
¾ The 2nd character is a numeric digit. It identifies the “type” of code
(Generic or Manufacturer-Specific).
Generic DTCs are codes that are used by all vehicle manufacturers.
The standards for generic DTCs, as well as their definitions, are set
by the Society of Automotive Engineers (SAE).
Manufacturer-Specific DTCs are codes that are controlled by the
vehicle manufacturers. The Federal Government does not require
vehicle manufacturers to go beyond the standardized generic DTCs
in order to comply with the new OBD2 emissions standards.
However, manufacturers are free to expand beyond the
standardized codes to make their systems easier to diagnose.
¾ The 3rd character is a numeric digit. It identifies the specific sys-tem or
sub-system where the problem is located.
¾ The 4th and 5th characters are numeric digits. They identify the section of
the system that is malfunctioning.
D900 CanScan 18
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