INPUT/OUTPUT SIGNAL CHART

Sensor | Input signal to ECM | ECM function | Actuator
Crankshaft position sensor (POS) Camshaft position sensor (PHASE) | Engine speed | Secondary air injection system control |

- Air pump relay
  ↓
  Air pump
- Air cut solenoid valve relay
  ↓
  Air cut solenoid valve

Secondary air injection system mass air flow sensor | Amount of secondary air
Engine coolant temperature sensor | Engine coolant temperature
Air fuel ratio (A/F) sensor 1 | Density of oxygen in exhaust gas
Battery | Battery voltage

SYSTEM DESCRIPTION

1. | Air pump cleaner | 2. | Secondary air injection system mass air flow sensor | 3. | Air pump
4. | Air cut solenoid valve | 5. | Air fuel ratio sensor 1 |  |
| : Secondary air |  |  |  |

During a cold start, the secondary air injection system supplies the air to the engine exhaust port so that the CO and HC burns and an increase in the temperature of the three way catalyst is facilitated. The three way catalyst is quickly activated and the emission gas during the cold start is reduced. When all of the following conditions are satisfied, the ECM activates the air pump, opens the air cut solenoid valve and supplies the secondary air to the exhaust port. The secondary air injection system operates for approximately a few tenths of a second depending on the engine coolant temperature and other conditions. When the system is deactivated, the ECM closes the air cut solenoid valve and stops the air pump to prevent the emission gas from blowing back.
< Activating conditions >

- When starting the engine
- Battery voltage: More than 10 V
- Engine coolant temperature at engine start is between 15 - 35 °C (59 - 95° F) and has lowered 45°C (113° F) or more since the latest engine stop.

SECONDARY AIR INJECTION SYSTEM LINE DRAWING

1. | Air pump cleaner | 2. | Air cut solenoid valve (bank 1) | 3. | Air cut solenoid valve (bank 2)
4. | Air pump | 5. | Secondary air injection system mass air flow sensor |  |
: Vehicle front