Possible causes

– Air Fuel Ratio Sensor 1 Bank 2 harness is open or shorted
– Air Fuel Ratio Sensor 1 Bank 2 circuit poor electrical connection
– Faulty Air Fuel Ratio Sensor 1 Bank 2

Tech notes

There is a service bulletin for the following models:

2005-2006 Nissan Altima
2005-2006 Nissan Altima Service Bulletin P1051 OBDII Code

2004 Nissan Maxima w/ 5 Speed Automatic Transmission
2004 Nissan Quest w/ 5 Speed Automatic Transmission
2004 Nissan Maxima, Quest Factory Service Bulletin P1051 OBDII Code

2004 Nissan Maxima w/ Manual Transmission or 4 Speed Automatic Transmission
2004 Nissan Quest w/ 4 Speed Automatic Transmission
2004 Nissan Maxima, Quest Factory Service Bulletin P1051 OBDII Code

2004 Nissan Armada
2004 Nissan Titan
2004 Nissan Armada/Titan Factory Service Bulletin P1051 OBDII Code

When is the code detected?

The current amperage in the heated air fuel ratio (A/F) sensor 1 heater circuit is out of the normal range. An excessively low voltage signal is sent to Engine Control Module (ECM) through the heated air fuel ratio (A/F) sensor 1 heater.

Symptoms

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

P1051 NISSAN Description

The Engine Control Module (ECM) performs ON/OFF duty control of the Air Fuel Ratio (A/F) sensor 1 heater corresponding to the engine operating condition to keep the temperature of A/F sensor 1 element at the specified range.

NISSAN Technical Service Bulletins for P1051 code