S10/T10 P/U 4WD V6-262 4.3L VIN Z (1992)
EGR Control Solenoid: Description and Operation
EVRV Circuit (Typical)
PURPOSE
To provide electrical control of the Exhaust Gas Recirculation (EGR) valve.
OPERATION
To regulate EGR flow, a control module controlled Electronic Vacuum Regulator Valve (EVRV) solenoid is used in the vacuum line. The control
module uses information from the following sensors to regulate the solenoid:
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Engine Coolant Temperature Sensor (ECT).
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Throttle Position Sensor (TP).
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Park/Neutral (P/N) switch.
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Distributor (RPM signal).
The EGR vacuum control has an EVRV solenoid that uses Pulse Width Modulation (PWM). This means the control module turns the solenoid ON
and OFF many times a second and varies the amount of ON time (pulse width) to vary the amount of EGR.