Possible causes

– Faulty Front Heated Oxygen Sensor Bank 1
– Front Heated Oxygen Sensor Bank 1 harness is open or shorted
– Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
– Inappropriate fuel pressure
– Faulty fuel injectors
– Intake air leaks may be faulty
– Exhaust gas leaks

Tech notes

Replacing the Front Heated Oxygen Sensor Bank 1 usually takes care of the problem.

There is a Nissan service bulletin for the following models:

2002 Nissan Sentra
2002 Nissan Altima
2002 Nissan Sentra and Altima Factory Service Bulletin OBDII Code P0134

When is the code detected?

The voltage from the sensor is constantly approx. 0.3V.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– High Fuel Consumption
– Excessive Smoke from Exhaust

P0134 NISSAN Description

The front heated oxygen sensor (or O2 sensor 1) is placed into the exhaust manifold. 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 Engine Control Module (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.

NISSAN Technical Service Bulletins for P0134 code