Exhaust Gas Recirculation: Testing and Inspection

3A-C, 3E & 4A-C ENGINES EXC. COROLLA FRONT WHEEL DRIVE

1. Inspect filter in EGR vacuum modulator and clean or replace as needed.
2. Connect vacuum gauge in line with EGR valve vacuum hose using suitable fitting.
3. Start engine and ensure engine runs properly at idle. If engine runs rough or stalls, check for improperly seated EGR valve.
4. With coolant temperature below 122°F, on 3A-C and 4A-C engines or 104°F, on 3E engine, run engine at 3000 RPM and observe vacuum gauge. If gauge reading is not zero, BVSV is defective.
5. Warm engine to normal operating temperature, and observe vacuum gauge at 3000 RPM. Gauge should indicate low vacuum.
6. If readings are not as specified, check for defective vacuum modulator.
7. Remove gauge and connect manifold vacuum to EGR valve with engine running at idle. If engine does not run rough or stall, check for defective EGR valve.

Fig. 31 EGR vacuum modulator & TVSV test.:

COROLLA FRONT WHEEL DRIVE W/4A-C & 4A-LC ENGINE

1. Inspect EGR vacuum modulator filter and clean or replace as needed.
2. Connect vacuum gauge in line with EGR valve vacuum hose using suitable fitting.
3. Start engine and ensure engine runs properly at idle. If engine runs rough or stalls, check for improperly seated EGR valve.
4. With coolant temperature below 122°F, run engine at 2000 RPM and observe vacuum gauge. If gauge reading is not zero, TVSV is defective.
5. Warm engine to normal operating temperature and observe gauge reading at 2000 RPM. Gauge should indicate low vacuum.
6. Disconnect vacuum hose from port ``R'' of vacuum modulator and connect manifold vacuum directly to port ``R'', Fig. 31. Vacuum gauge should indicate high vacuum at 2000 RPM.
7. If improper readings are obtained in steps 5 and 6, check for defective vacuum modulator.
8. Remove vacuum gauge and adapter, reconnect proper vacuum hose to modulator, then apply manifold vacuum directly to EGR valve.
9. If engine does not run rough at idle or stall, EGR valve is defective.