P0031

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

OUTLINE OF DIAGNOSIS
Detect the open or short circuit of front oxygen (A/F) sensor heater. Diagnosis is performed using front oxygen (A/F) sensor IC, and communication is established between front oxygen (A/F) sensor IC and main IC. Front oxygen (A/F) sensor IC judges NG when the data of voltage and current is abnormal with heater turned on or off.




COMPONENT DESCRIPTION




ENABLE CONDITION

GENERAL DRIVING CYCLE
Always perform diagnosis continuously.

DIAGNOSTIC METHOD




Front oxygen (A/F) sensor IC judges NG when the continuous time of completing the malfunction criteria becomes more than the time needed for diagnosis (4.5 seconds). Front oxygen (A/F) sensor IC judges OK and clear NG when the malfunction criteria are not completed.

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
- Front oxygen (A/F) sensor heater control: Not allowed to turn on heater
- Front oxygen (A/F) sensor main learning correction: Not allowed to calculate
- Rear oxygen (A/F) sensor sub learning correction: Not allowed to calculate
- Correction when re-starting at high temperature: Normally minimum value 0.06 -> 0
- Purge control: Not allowed to purge

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