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Home >> Nissan-Datsun >> 2008 >> Altima Base >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (Engine Control System (Hybrid)) >> Component Diagnosis >> P0139 Ho2S2 >> DTC Logic >> DTC Detection Logic
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DTC Detection Logic

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The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen storage capacity of the three way catalyst (manifold) causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the switching response of the sensor's voltage is faster than specified during the various driving condition such as fuel-cut.

Fig 1: Voltage Graph
G05694990Courtesy of NISSAN MOTOR CO., U.S.A.
DTC DETECTING CONDITION AND POSSIBLE CAUSE

DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139 Heated oxygen sensor 2 circuit slow response It takes more time for the sensor to respond between rich and lean than the specified time.
  • Harness or connectors

    (The sensor circuit is open or shorted)

  • Heated oxygen sensor 2
  • Fuel pressure
  • Fuel injector
  • Intake air leaks
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