P0031

DTC P0031 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 1)

1. OUTLINE OF DIAGNOSIS
Detect the open or short circuit of front oxygen (A/F) sensor heater.
The front oxygen (A/F) sensor 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.




2. COMPONENT DESCRIPTION




3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE
Always perform diagnosis continuously.

5. DIAGNOSTIC METHOD




^ Abnormality Judgment
Judge NG when the continuous time of completing the malfunction criteria below becomes more than 1 second (8 cycles).




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

6. DTC CLEAR CONDITION
^ When the OK idling cycle was completed 40 times in a row
^ When "Clear Memory" was performed

7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITION
^ When the OK driving cycle was completed 3 times in a row
^ When "Clear Memory" was performed

8. FAIL SAFE
^ Front oxygen (A/F) sensor activation judgment: Front oxygen (A/F) sensor full activation is not complete, or front oxygen (A/F) sensor half activation is not complete.
^ Front oxygen sensor main learning correction: Not allowed to calculate.
^ Compensation when starting the engine at high temperature: Make the MIN value to be 0 from 0.3 normally.
^ Purge control: Not allowed to purge.

9. ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)