Dec 052010
 

got a po139;o2 signal slow.bank #1 sensor #2.cleared codes.ok so far.did quick check of signal ok. refresh my old age memory. u look at the engine standing in front of front bumper 2 c which is left/right,yes?so my problem is 2 the left(?) & which o2 unit? front or rear? also got a po1147;undocumented code. what does this mean & will it affect my car/emmissions etc? thx all

  One Response to “2002 nissian maxima-3.5L-loaded”

  1. You stand in front of the engine(where the alternator, water pump, belts are) to determine left ore right. On the nissan the left side is bank 1 and the right side is bank #2.

    Sensor #1 is the one closest to the engine or Pre-catalytic converter and Sensor #2 is After the catalytic Converter.

    P1147 NISSAN Description

    The heated oxygen sensor 2 (rear), after three way catalyst, monitors the oxygen level in the exhaust gas on each bank.
    Even if switching characteristics of the heated oxygen sensor 1 (front) are shifted, the air fuel ratio is controlled to stoichiometric, by the signal from the heated oxygen sensor 2.
    This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1V in richer conditions to 0V in leaner conditions.
    Under normal conditions the heated oxygen sensor 2 is not used for engine control operation.

    When is the code detected?The P1147 code is triggered when the maximum voltage from the sensor is not reached to the specified voltage.

    Possible Causes– The O2 Sensor harness or connectors circuit is open or shorted
    – Heated oxygen sensor 2
    – Fuel pressure
    – Injectors
    – Intake air leaks

    Possible Solution:Replacing the O2 Sensor 2 usually takes care of the problem

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