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DTC - Diagnostic Trouble Codes information

P1143

Powertrain Codes

P1143 - NISSAN - Heated Oxygen Sensor 1 Lean Shift Monitoring Bank 1

Symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

Possible Causes

- Front Heated Oxygen Sensor Bank - Front Heated oxygen sensor 1 heater - Fuel pressure - Injectors - Intake air leaks

When Detected

The maximum and minimum voltage from the sensor are not reached to the specified voltages.

Tech Notes

If there are no intake air leaks, the most likely cause of the P1143 code is the front O2 sensor bank 1.

Description

The heated oxygen sensor 1 is placed into the front tube. It detects the amount of oxygen in the exhaust gas compared to the outside air. The heated oxygen sensor 1 has a closed-end tube made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions. The heated oxygen sensor 1 signal is sent to the ECM. The ECM adjusts the injection pulse duration to achieve the ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical change from 1V to 0V.