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Home >> Hyundai >> 2017 >> Elantra Eco >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis - 1.4L (1 Of 3) >> DTC P0139: O2 Sensor Circuit Slow Response (Bank 1/Sensor 2) >> DTC Information >> DTC Detecting Condition
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DTC Information: DTC Detecting Condition

Item Detecting Condition Possible Cause
DTC Strategy
  • Rationality check
  1. Poor connection
  2. B1S2
  3. ECM
Case1 Enable Conditions
  • Battery voltage is higher than 10.7V
  • Engine speed is between 1200 RPM and 3520 RPM
  • EGT around downstream O2S is higher than 797°F (425° C)
  • Exhaust gas mass flow is higher than 6kg/h
  • Delta exhaust gas mass flow is between -150kg/h and 150kg/h
  • Fuel cut off
  • Downstream O2S voltage before fuel cut is higher than 0.63V
Threshold Value
  • Response Time is higher than 0.3 sec.

    (Duration of Downstream O2S voltage from above 0.63V to 0.25V during fuel cut off)

  • Transient Time is higher than Threshold

    (When downstream O2S voltage changes from 0.63V during fuel cut off)
Case 2 Enable Conditions
  • Battery voltage is higher than 10.7V
  • Engine speed is between 1200 RPM and 3520 RPM
  • EGT around downstream O2S is higher than 797°F (425° C)
  • Exhaust gas mass flow is higher than 15kg/h
  • Delta exhaust gas mass flow is between -70kg/h and 150kg/h
  • Fuel cut in
  • Downstream O2S voltage before fuel cut-in is lower than 0.25V
Threshold Value
  • Response Time is higher than 2.2 sec.

    (Duration of Downstream O2S voltage from above 0.63V to 0.25V during fuel cut in)

  • Transient Time is higher than Threshold

    (When downstream O2S voltage changes from 0.25V during fuel cut in)
Diagnostic Time
  • 2 valid fuel cut-in phases
MIL ON Condition
  • 2 driving cycle
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