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DTC P0038 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 2)

DTC P0038 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 2)

OUTLINE OF DIAGNOSIS

Detect open or short circuit of oxygen heater.

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.

Judge NG when the terminal voltage remains to be High.

COMPONENT DESCRIPTION


(A)

Battery voltage

(C)

256 milliseconds (cycles)

(B)

Oxygen sensor heater output voltage

(D)

High malfunction



ENABLE CONDITION

Secondary Parameters Enable Conditions
Battery voltage

> 10.9 V

Elapsed time after engine starting

≥ 1 second



GENERAL DRIVING CYCLE

Perform the diagnosis continuously after engine starting.

DIAGNOSTIC METHOD

Abnormality Judgment

Judge NG when the continuous time of completing all the malfunction criteria below becomes more than 2560 milliseconds (10 cycles).

Judgment Value

Malfunction Criteria Threshold Value
Output voltage level

High

Oxygen sensor heater control duty

≥ 20%



Time Needed for Diagnosis: 2.56 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

Normality Judgment

Judge OK and clear the NG when all the malfunction criteria below are completed.

Judgment Value

Malfunction Criteria Threshold Value
Output voltage level

Low



DTC CLEAR CONDITION


When the OK idling cycle was completed 40 times in a row

When “Clear Memory” was performed


MALFUNCTION INDICATOR LIGHT CLEAR CONDITION


When the OK driving cycle was completed 3 times in a row

When “Clear Memory” was performed


FAIL SAFE

Sub feedback control: Not allowed

ECM OPERATING AT DTC SETTING

Memorize the freeze frame data. (For test mode $02)