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California Emission Regulation Applicable ATX Model

DTC P0139 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0139 Middle HO2S circuit problem
DETECTION CONDITION 
  • The PCM monitors inversion cycle period, middle HO2S output voltage inclination. The PCM detects that the voltage inclinations are below threshold consecutive 5 times  when following conditions are met, or 0.3 V or more  is detected three times even though fuel cut is performed for 3 s or more,  the PCM determines that circuit has malfunction.

    MONITORING CONDITIONS 

    • HO2S heater, HO2S, and TWC Repair Verification Drive Mode
    • Following conditions are met:
      • Engine speed is 500 RPM or above. 
      • Engine coolant temperature is above 70 ° C {158 ° F}. 

Diagnostic support note 
  • This is an intermittent monitor. (HO2S)
  • MIL illuminates if PCM detects above malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in PCM.
  • DIAGNOSTIC MONITORING TEST RESULTS is available.
  • PENDING CODE is available if PCM detects the above malfunction condition during first drive cycle.
  • FREEZE FRAME DATA is available.
  • DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • Middle HO2S deterioration
  • Middle HO2S malfunction
  • Looseness middle HO2S
  • Pressure regulator (built-in fuel pump unit) malfunction
  • Fuel pump malfunction
  • Fuel filter (built-in fuel pump unit) clogged or restricted
  • Fuel leakage on fuel line from fuel distribution pipe and fuel pump
  • Leakage exhaust system
  • Purge solenoid valve malfunction
  • Purge solenoid hoses improper connection
  • Insufficient compression
  • Engine malfunction (Leakage engine coolant)