EMISSION CONTROL SYSTEM


  1. CONSTRUCTION


    1. The air pressure sensor consists of a semiconductor, which has a silicon chip that changes its electrical resistance when pressure is applied to it. The sensor converts the pressure into an electrical signal, and sends it to the ECM in an amplified form.

    2. The air pressure sensors for bank 1 and bank 2 have the same basic structure and function.

      A019R1TE03

    3. The ECM detects operation of the air injection system based on signals from the air pressure sensor as follows:


      1. When the air pump is on and the air switching valve assembly is closed, the pressure is stable.

      2. When the air pump is on and the air switching valve assembly is open, the pressure drops slightly and becomes unstable because of exhaust pulses.

      3. When the air pump is off and the air switching valve assembly is closed, the pressure remains at atmospheric pressure.

      4. When the air pump is off and the air switching valve assembly is open, the pressure drops below atmospheric pressure and becomes unstable because of exhaust pulses.

      A019QLDE04