Starlet & Tercel
- Using a 3-way connector, connect a vacuum gauge to EGR vacuum hose. Start engine and run at idle speed.
- With coolant temperature below 106°F (41°C) on Starlet or 122°F (50°C) on Tercel, vacuum gauge should indicate zero at 2000 RPM on Starlet or 2500 RPM on Tercel. When engine is warm, low vacuum should be present.
- Disconnect vacuum hose from EGR vacuum modulator port "R". Using a jumper hose, connect port "R" to intake manifold vacuum. Vacuum gauge should indicate high vacuum at 2000 RPM on Starlet or 2500 RPM on Tercel.NOTE: Engine will misfire slightly at this time, as a large amount of EGR gas enters.
- On Tercel, disconnect and plug vacuum hose from port "S" of EGR vacuum modulator. Using a jumper hose, connect port "S" to intake manifold vacuum. Vacuum gauge should indicate low vacuum at 2500 RPM.
- On all models, remove gauge and reconnect hoses. If system performed as described, it is operating correctly. If not, test individual components and repair or replace as necessary.