EGR Control Solenoid: Description and Operation

Fig. 21 Testing VSV Operation:

PURPOSE
The EGR vacuum switching valve is turned on by a signal from the ECM.

OPERATION
The EGR is disabled to maintain driveability, any one of the following conditions will cause the ECM to disable the EGR:

^ Engine coolant temperature below 140°F (60°C)
^ During deceleration (throttle valve closed)
^ Light engine load (small amount of intake air)
^ Engine speed over 4,000 rpm
^ Engine racing