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DTC P0139, P0159: Notes

DTC P0139, P0159 [AJ] DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0139 HO2S (Rear, RH) slow response
DTC P0159 HO2S (Rear, LH) slow response
DETECTION CONDITION 
  • The PCM monitors the rich (0.4 V  ) to lean (0.3 V  ) response time of the HO2S (RR, LR). The PCM measures the response time when the following conditions are met. The PCM determines the HO2S (RR, LR) response deterioration malfunction when the measured response time is more than the threshold value (180 ms  ) five consecutive times.

    MONITORING CONDITIONS 

    • Drive mode 3
    • The following conditions are met:
      • Fuel cut during deceleration.
      • Engine speed is above 500 rpm. 
      • Engine coolant temperature is above 70 °C {158 CF}. 
      • HO2S (RR, LR) output voltage is above 0.4 V. 
  • The PCM monitors for a time-out malfunction (when HO2S (RR, LR) remains above 0.3 V  for longer than a specified period of time during fuel cut control). The PCM measures the amount of time from when the following conditions are met until the HO2S (RR, LR) output voltage drops below 0.3 V.  The PCM determines a HO2S time-out malfunction when the detected time is more than the threshold value (6 s  ) three consecutive times.

MONITORING CONDITIONS 

  • Drive mode 3
  • The following conditions are met:
  • Fuel cut during deceleration.
  • Engine speed is above 500 rpm. 
  • Engine coolant temperature is above 70 °C {158 °F}. 
  • HO2S (RR, LR) is activated (more than 0.55 V  ).

Diagnostic support note 

  • This is an intermittent monitor. (HO2S)
  • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
  • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
  • FREEZE FRAME DATA is available.
  • The DTC is stored in the PCM memory.
  • DIAGNOSTIC MONITORING TEST RESULT is available.
POSSIBLE CAUSE 
  • HO2S (LR, RR) deterioration
  • HO2S (LR, RR) malfunction
  • Loose HO2S (LR, RR)
  • 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 distributor pipe and fuel pump
  • Purge solenoid valve malfunction
  • Improper connection of purge solenoid hoses
  • Insufficient compression
  • Engine malfunction (Engine coolant leakage)