EGR System: Corolla
- Using a 3-way connector, connect a vacuum gauge to vacuum hose between EGR valve and EGR vacuum modulator. Start engine and run at idle speed.
- With coolant temperature below 104°F (40°C), increase engine speed to 3000 RPM. Vacuum gauge should indicate zero.
- Warm up engine to normal operating temperature. Vacuum gauge should indicate low vacuum at 3000 RPM. Apply manifold vacuum directly to EGR valve with engine idling. Engine should run rough or die.
- Remove gauge and reconnect hose. If system performed as described, it is operating correctly. If not, test individual components and repair or replace as necessary.
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