Test 3
- Warm engine to normal operating temperature. Operate engine at idle. Attach a vacuum gauge to EGR vacuum hose. Locate EGR vacuum solenoid.
- Using a jumper wire, ground signal wire from ECM to EGR vacuum solenoid. Vacuum should be present at EGR vacuum hose. On some models, engine speed may have to be increased 3000-4000 RPM.
- Connect a hand-held vacuum pump to EGR valve. Start engine. Apply vacuum to EGR valve. If engine runs rough or stalls, and gauge holds vacuum, EGR valve is functioning properly.