DTC P0031 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 1)
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DTC P0031 HO2S HEATER CONTROL CIRCUIT LOW
(BANK 1 SENSOR 1)
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Detect the open or short circuit of heater.
The heater conducts the duty control. The
output terminal voltage at ON becomes 0 V, and the output terminal
voltage at OFF becomes battery voltage.
Judge NG when the terminal voltage remains
to be Low.
(A)
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Battery
voltage
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(C)
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128 milliseconds
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(B)
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Front oxygen (A/F) sensor heater output voltage
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(D)
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Low abnormality
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Secondary
Parameters
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Enable
Conditions
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Battery
voltage
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≥ 10.9
V
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Always perform diagnosis continuously.
Abnormality Judgment
Judge NG when the continuous time of completing
the malfunction criteria below becomes more than 1 second (8 cycles).
Judgment Value
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Malfunction
Criteria
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Threshold
Value
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Output
voltage level
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Low
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Front oxygen
(A/F) sensor heater control duty
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< 87.5%
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Time Needed for Diagnosis:
1
second
Malfunction Indicator
Light Illumination:
Illuminates as soon as malfunction occurs.
Normality Judgment
Judge OK and clear the NG when all the malfunction
criteria below are completed.
Judgment
Value
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Malfunction
Criteria
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Threshold
Value
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Output
voltage level
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High
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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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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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Front oxygen (A/F) sensor heater control:
Not allowed to turn on the heater.
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A/F main learning: Not allowed
to calculate the A/F main learning compensation factor.
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A/F sub learning: Not allowed
to calculate the A/F sub learning compensation factor.
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•
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Compensation when starting the engine
at high temperature: Make the MIN value to be 0 from 0.06 normally.
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Purge control: Not allowed to purge.
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ECM OPERATING
AT DTC SETTING
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Memorize the freeze frame data. (For test
mode $02)
