Heavy Duty & OBDII Diagnostic Tool HD V3.0
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2. Which, if any, Diagnostic Trouble Codes (DTCs) are stored;
3. Readiness Monitor status.
2.2 Diagnostic Trouble Codes (DTCs)
Diagnostic Trouble Codes (DTCs) 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 the intended to
provide you with a guide as to where a fault might be occurring within a
vehicle.
2.2.1
OBDII DTC
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 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:
