DTC P0508 IDLE CONTROL SYSTEM CIRCUIT LOW
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DTC P0508 IDLE CONTROL SYSTEM CIRCUIT LOW
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Detect open or short circuit in idle air
control solenoid valve.
Period of idle air control solenoid valve
is 4 milliseconds and it is too short.
Judge OK/NG in accordance with the
number of change of OFF to ON signal.
(1)
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Engine
control module (ECM)
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(2)
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Detecting
circuit
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(3)
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Battery
voltage
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(4)
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Main relay
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(5)
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Idle air
control solenoid valve
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Secondary
Parameters
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Enable
Conditions
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After
engine starting
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1
second or more
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Idle
air control solenoid valve duty ratio
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5 — 95%
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Battery
voltage
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≥ 10.9
V
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Perform the diagnosis after starting the
engine.
Judge NG when the malfunction criteria below
are completed. Judge OK and clear NG when the malfunction criteria
below are not completed.
Judgment
Value
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Malfunction
Criteria
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Threshold
Value
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Number
of change that idle air control solenoid valve signal during 64
milliseconds.
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≤ 8
(160 at normal since the cycle is 4 milliseconds)
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Time Needed for Diagnosis:
64
milliseconds
Malfunction Indicator
Light Illumination:
Illuminates as soon as malfunction occurs.
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•
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When the OK idling cycle was completed 40 times
in a row
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•
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When “Clear Memory” was
performed
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MALFUNCTION
INDICATOR LIGHT CLEAR CONDITION
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•
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When the OK driving cycle was completed 3 times
in a row
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•
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When “Clear Memory” was
performed
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•
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Idle air control solenoid valve feedback correction:
Not allowed to calculate ifb (idle air control solenoid valve feedback
amount)
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•
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Fuel shut-off: Shut-off fuel for only #1
and #2 cylinder, or for all cylinder in accordance with
vehicle speed, engine speed, throttle position
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•
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Judgment of heavy fuel: Not allowed
to make the judgment of heavy fuel
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ECM OPERATION
AT DTC SETTING
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Memorize the freeze frame data. (For test
mode $02)
