Possible causes

– Faulty air fuel ratio (A/F) sensor 1 heater Bank 1
– Air fuel ratio (A/F) harness is open or shorted
– Air fuel ratio (A/F) circuit poor electrical connection

When is the code detected?

The A/F signal computed by ECM from the A/F sensor 1 signal is constantly approx. 0V.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Possible rough engine idle

P1272 NISSAN Description

The A/F sensor is a planar dual-cell limit current sensor. The sensor element of the A/F sensor is the combination of a Nernst concentration cell (sensor cell) with an oxygen-pump cell, which transports ions. It has a heater in the element.

The sensor is capable of precise measurement