Roadmaster V8-350 5.7L VIN P MFI (1995)
EGR Electronic Vacuum Regulator Solenoid: Description and Operation
The Exhaust Gas Recirculation (EGR) vacuum control has a vacuum control solenoid that is controlled by Pulse Width Modulation (PWM). This means
that the Powertrain Control Module (PCM) turns the solenoid "OFF" and "ON" many times a second and varies the amount of "ON" time (pulse width)
to vary the amount ported manifold vacuum to the EGR valve.
The PCM uses RPM and information from the following sensors to regulate the EGR solenoid valve:
^
Engine Coolant Temperature (ECT) sensor.
^
Intake Air Temperature (IAT) sensor.
^
Throttle Position (TP) sensor.
^
Manifold Absolute Pressure (MAP) sensor.
^
Park/Neutral Position (PNP) switch.
^
Vehicle Speed Sensor (VSS).
Grounding the Data Link Connector (DLC) output / field service enable terminal with the ignition "ON" and the engine not running will energize the
solenoid valve and allow vacuum to the EGR valve.
