Operation

EGR Valve Assembly Sectional View:

The EGR valve is designed to supply EGR to the engine. The EGR valve consists of a sealed bobbin and coil assembly, or solenoid. Inside the solenoid is a sleeve-armature assembly that contains a pintle and valve, two seals, retaining washers, a seal spring, and armature spring, and a bearing. The bearing seals the pintle valve shaft from the exhaust chamber. Also, a shield, held in place by a compression spring, deflects exhaust gas from the shaft and armature.

The Powertrain Control Module (PCM) uses the pintle valve to control the EGR flow into the engine. Exhaust gas is routed from the intermediate exhaust pipe to the valve through a feedpipe. When the PCM commands the EGR valve open, the exhaust flows through the EGR valve, past the pintle and into the engine via the crossover water pump housing. When the throttle valve opens, the exhaust gas mixes with the incoming air. When the combination of air/fuel/exhaust gas is burned in the chamber, a portion of the heat energy is absorbed by the exhaust gas. This helps to lower the level of NOx emissions.

The PCM monitors the pintle position using the signal from the EGR pintle position sensor. The sensor is an integral part of the EGR valve. The PCM supplies the pintle position sensor with a 5-volt reference and a ground. The pintle position sensor provides a signal voltage to the PCM. By monitoring the voltage on the signal line, the PCM is able to determine if the EGR valve responds properly to commands from the PCM. As the EGR valve position changes, the pintle position signal voltage will change. With the EGR valve closed, the signal voltage is near 0 volts. However, the pintle position signal voltage increases as the EGR valve opens.