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DTC Detection Logic

WARNING: This page is about a different car, the 2008 Infiniti EX35. However, it is still accessible from the selected car via links, so may be relevant.

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 1 causes the longer switching time. To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the maximum voltage of the sensor is sufficiently high during the various driving condition such as fuel-cut.

Fig 1: Identifying Voltage Waveform
G04875059Courtesy of NISSAN MOTOR CO., U.S.A.
DTC DETECTING CONDITION AND POSSIBLE CAUSE REFERENCE

DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0137 Heated oxygen sensor 2 (bank 1) circuit low voltage The maximum voltage from the sensor is not reached to the specified voltage.
  • Harness or connectors

    (The sensor circuit is open or shorted)

  • Heated oxygen sensor 2
  • Fuel pressure
  • Fuel injector
  • Intake air leaks
P0157 Heated oxygen sensor 2 (bank 2) circuit low voltage
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