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Home >> Infiniti >> 2017 >> QX80 Base, RWD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (DTCS) (2 Of 4) >> DTC/Circuit Diagnosis >> 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 (manifold) 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 various driving conditions such as fuel cut.

G05979025Courtesy of NISSAN NORTH AMERICA, INC.
DTC No. Trouble diagnosis name
(Trouble diagnosis content)		 DTC detecting condition Possible cause
P0137 HO2S2 (B1)
[Heated oxygen sensor 2 (bank 1) circuit low voltage]
  • The maximum voltage from the sensor does not reach the specified voltage.
  • ECM detects the heated oxygen sensor 2 heater circuit is short to ground.
  • Harness or connectors

    (The heated oxygen sensor 2 circuit is open or shorted)

  • Heated oxygen sensor 2
  • Fuel pressure
  • Fuel injector
  • Intake air leaks
P0157 HO2S2 (B2)
[Heated oxygen sensor 2 (bank 2) circuit low voltage]
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