EGR Valve control

EGR Valve control

The EGR system is used to reduce oxides of nitrogen emissions (NOX) by recirculating exhaust gas and combining it with the air/fuel mixture. The exhaust gas is recirculated through the EGR valve to the intake manifold. The ECM regulates the EGR valve by turning the EGR solenoid on and off.

When the ignition switch is on, voltage is applied to the EGR solenoid via a B/Y wire from fuse 4. The ECM controls the EGR solenoid by providing an earth supply via a R wire.

Intake Air Bypass (IAB) Solenoid control (2.3l only)

The intake manifold contains two air intake paths to allow selection of the intake path which provides satisfactory power performance at a given engine speed. When the engine speed is below 4,800 rpm, the ECM supplies earth to the IAB solenoid via a K/U wire. The solenoid energises and intake air flows through the long path to deliver high torque. At higher engine speeds the ECM removes the earth supply to the IAB solenoid. The solenoid deenergises and intake air flows through the short path to reduce the resistance in airflow.

Intake Air Control Solenoid control (2.3l only)

The intake air control solenoid is used to decrease air intake noise. When the engine speed is below 3,900 rpm, the ECM supplies earth to the solenoid via a W wire. This opens the solenoid valve and sends intake manifold vacuum to the intake air control diaphragm.

A/C Compressor Clutch control

When the ECM receives the A/C ON signal it provides earth to the coil of the compressor clutch relay via a R/W wire. The relay energises, providing voltage to the compressor clutch.

A/C Condenser Fan control

When the A/C system is ON and the ECM determines that Condenser fan operation is required, the ECM provides earth to the condenser fan relay via a R/W wire, U wire, A/C diode, and a U/B wire. The relay energises, providing voltage to the condenser fan.