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Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 2388 (Engine Control System - DTCS U1000 To P0159) >> DTC P0137, P0157 Ho2S2 >> On Board Diagnosis Logic

On Board Diagnosis Logic

WARNING: This page is about a different car, the 2007 Nissan Pathfinder. 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 (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 the various driving condition such as fuelcut.

Fig 1: Identifying Heated Oxygen Sensor Voltage Waveform
G04875059Courtesy of NISSAN NORTH AMERICA, INC.
DTC DETECTING CONDITION POSSIBLE CAUSE

DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0137
0137
(Bank 1)
Heated oxygen sensor 2 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
0157
(Bank 2)