Possible causes

– Faulty Swirl Control Valve Control Position Sensor
– Swirl Control Valve Control Position Sensor harness is open or shorted
– Swirl Control Valve Control Position Sensor circuit poor electrical connection
– Faulty Swirl Control Valve

When is the code detected?

The P1138 code is detected when the target opening angle of swirl control valve controlled by Engine Control Module (ECM) and the input signal from swirl control valve position sensor is not in the normal rang.

Symptoms

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

P1138 INFINITI Description

While idling and during low engine coolant temperature, the swirl control valve closes, Thus the velocity of the air in the intake passage increases, promoting the vaporization of the fuel and producing a swirl in the combustion chamber.
Because of this operation, this system tends to increase the burning speed of the gas mixture, improve fuel consumption, and increase the stability in running conditions.
Also, except when idling and during low engine coolant temperature, this system opens the swirl control valve.
In this condition, this system tends to increase power by improving intake efficiency via reduction of intake flow resistance, intake flow.
The swirl control valve is operated by the Engine Control Module (ECM).