A
malfunction indicator lamp (
MIL), commonly referred
to as the "Check Engine Light" is an indicator of malfunction of the
computerized engine management system. It is found on the instrument
console of most automobiles. When illuminated, it is typically either an
amber or red color. On vehicles equipped with
OBD-II,
the light has two stages: steady (indicating a minor fault such as a
loose gas cap or failing
oxygen
sensor) and flashing (indicating a severe fault, that will
eventually destroy the catalytic converter, such as a misfire). When the
MIL is lit, the
engine
control unit stores a fault code related to the malfunction, which
can be retrieved with a
scan
tool and used for further diagnosis. The malfunction indicator lamp
is usually labeled with the text
check engine,
service engine
soon,
check engine soon, or a picture of an engine.
The MIL appeared in the early 80s along with computerized engine
controls. Even the earliest systems, such as GM's CCC (Computer Command
Carburetor) system had self diagnosis functionality. When the computer
detected a fault, it illuminated the MIL. Up until OBDII, on most cars
the MIL could output codes, when two pins on the ALDL are jumped, the
light would flash the codes, for instance (blink) (pause) (blink)
(blink) for code 12. Some manufacturers retained this feature even after
OBDII, such as Honda.
Hope this help (remember comment and rated this). Good luck.
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