DTC P0030: Ho2S Heater Control Circuit (Bank 1 Sensor 1)

Detect the malfunction of front oxygen (A/F) sensor heater.

Diagnosis is performed using A/F microcomputer, and communication is established between A/F microcomputer and main microcomputer. Judge NG when the data of heater malfunction NG is transmitted.

Judge NG when the front oxygen (A/F) sensor element impedance is out of the standard value.

Perform the diagnosis continuously in 30 seconds after the heater continuity starting, and complete the diagnosis if making a NG judgment.

• Abnormality Judgment 

  Judge NG when one of the malfunction criteria below is completed.

  Judgment Value 

  JUDGMENT VALUE (ABNORMALITY JUDGMENT)
  
  

  Malfunction Criteria	Threshold Value
  Impedance of front oxygen (A/F) sensor	< 10 Ω or> 40 Ω

  Time Needed for Diagnosis:  120 seconds

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

• Normality Judgment 

  Judge OK when all of the malfunction criteria below is completed.

  Judgment Value 

  JUDGMENT VALUE (NORMALITY JUDGMENT)
  
  

  Malfunction Criteria	Threshold Value
  Impedance of front oxygen (A/F) sensor	10 - 40Ω

• When the OK idling cycle was completed 40 times in a row
• When "Clear Memory" was performed

• When the OK driving cycle was completed 3 times in a row
• When "Clear Memory" was performed

None

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