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Home >> Infiniti >> 2011 >> EX35 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0130 Through P0445 >> DTC P0137, P0157: Ho2S2 >> DTC Logic >> DTC Detection Logic
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DTC Detection Logic

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: Heated Oxygen Sensor 2 Waveform
G07165018Courtesy of NISSAN MOTOR CO., U.S.A.
DTC DETECTION LOGIC

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