DTC P0038 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 2)
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DTC P0038 HO2S HEATER CONTROL CIRCUIT HIGH
(BANK 1 SENSOR 2)
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Detect open or short circuit of rear oxygen
heater. Rear oxygen heater conducted the duty control, and the output
terminal voltage at ON is 0 V and the output terminal voltage at
OFF is the battery voltage. Calculate the Max. and Min. values of
heater output terminal voltage. When the Min. value does not decreased,
it means High malfunction.
(A)
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Battery
voltage
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(B)
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Rear oxygen
sensor heater output voltage
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(C)
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262 milliseconds
(cycles)
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(D)
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High malfunction
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Secondary
Parameters
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Enable
Conditions
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Before
or after starting the engine
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After
starting the engine
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Battery
voltage
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> 10.9
V
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Duty
ratio of heater output
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19.9 ←→ 79.6%
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Engine
speed
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< 4,500
rpm
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Perform the diagnosis continuously after
engine starting.
Judge NG when the continuous time of completing
the malfunction criteria below becomes more than 5 seconds. Judge
OK and clear the 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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Min. heater
voltage
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> 1.92
V
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Time Needed for Diagnosis:
5
seconds
Malfunction Indicator
Light Illumination:
Illuminates when malfunction occurs in
2 continuous driving cycles.
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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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Sub feedback control: Not allowed
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ECM OPERATING
AT DTC SETTING
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Memorize the freeze frame data. (For test
mode $02)
