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Home >> Nissan-Datsun >> 2019 >> Maxima SL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTC/Circuit Diagnosis) (2 Of 5) >> DTC/Circuit Diagnosis >> DTC P0138: Ho2S2 >> DTC Description >> 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.

MALFUNCTION 1

To judge the malfunctions of heated oxygen Sensor 2, ECM monitors whether the voltage is unusually high during various driving conditions such as fuel cut.

GNSJSBIA4884GB-884Courtesy of NISSAN NORTH AMERICA, INC.

SYMBOL

: 1.3 V

MALFUNCTION 2

To judge the malfunctions of heated oxygen Sensor 2, ECM monitors whether the minimum voltage of Sensor is sufficiently low during various driving conditions such as fuel-cut.

GNSJSBIA5834Z-834Courtesy of NISSAN NORTH AMERICA, INC.
  1. An excessively high voltage from the Sensor is sent to ECM.
  2. The minimum voltage from the Sensor is not reached to the specified voltage.

DTC

CONSULT screen terms

(Trouble diagnosis content)

DTC detection condition

P0138

HO2S2 (B1)

(O2 Sensor circuit high voltage bank 1 Sensor 2)

1

Diagnosis condition

--

Signal (terminal)

Voltage signal transmitted from heated oxygen Sensor 2 to ECM

Threshold

An excessively high voltage from the Sensor is sent to ECM

Diagnosis delay time

--

2

Diagnosis condition

--

Signal (terminal)

Voltage signal transmitted from heated oxygen Sensor 2 to ECM

Threshold

The minimum voltage from the Sensor is not reached to the specified voltage

Diagnosis delay time

--

P0158

HO2S2 (B2)

(O2 Sensor circuit high voltage bank 2 Sensor 2)

1

Diagnosis condition

--

Signal (terminal)

Voltage signal transmitted from heated oxygen Sensor 2 to ECM

Threshold

An excessively high voltage from the Sensor is sent to ECM

Diagnosis delay time

--

2

Diagnosis condition

--

Signal (terminal)

Voltage signal transmitted from heated oxygen Sensor 2 to ECM

Threshold

The minimum voltage from the Sensor is not reached to the specified voltage

Diagnosis delay time

--