System Check: Notes
- With engine cold, disconnect vacuum hose from EGR valve at manifold and connect vacuum gauge to hose. Start engine and slowly raise to 4500 RPM. No vacuum should be shown on gauge.
- If vacuum is present, check for voltage at EGR control solenoid valve A. If voltage is present, replace valve and retest. If no voltage, check wiring, fuse, and thermosensor A.
- Disconnect vacuum hose from EGR valve and connect vacuum gauge to hose. Take off control box cover by removing 3 screws. Put positive probe of voltmeter in Blue/White wire connector at EGR control solenoid valve A. Put negative probe to good ground.EGR System Test
Condition of Engine EGR Valve Vacuum Blue/White Wire Voltage Idle None None 4500 RPM Yes None 4500 RPM with Blocked EGR Bleed (1) Less Than 2 in. Hg None Hard Acceleration over 15 MPH (2) Yes None Deceleration over 15 MPH (2) None Yes (1) See Figure. (2) In second gear or "2". - Raise front of vehicle and support with safety stands. Start engine and wait for engine to warm up (cooling fan comes out). Vacuum and voltage should match specifications given in "EGR System Test" chart.
- If all readings are correct, check EGR valve for proper operation. If vacuum of more than 2 in. Hg is noted (but no voltage) replace EGR control valve and check vacuum hose routing. If any other readings are not correct, perform all other tests in sequence.