Component Tests and General Diagnostics

EGR SYSTEM INSPECTION




1. Inspect and clean filter in EGR vacuum modulator.
(a) Remove the cap and filter.
(b) Check the filter for contamination or damage.
(c) Using compressed air. clean the filter.
(d) Reinstall the filter and cap.

HINT: Install the filter with the coarser surface facing the atmospheric side (outward).




2. Install vacuum gauge.
Using a 3-way connector, connect a vacuum gauge to the hose between the EGR valve and EGR vacuum modulator.
3. Inspect seating of EGR valve.
Start the engine and check that the engine starts and runs at idle.
4. Connect Toyota hand-held tester or OBD II scan tool.
5. Inspect VSV operation with cold engine.
(a) The engine coolant temperature should be below 47°C (117°F).
(b) Check that the vacuum gauge indicates zero at 2,500 rpm.
(c) Check that the EGR pipe is not hot.




6. Inspect operation of VSV and EGR vacuum modulator with hot engine.
(a) Warm up the engine to above 53°C (127°F).
(b) Check that the vacuum gauge indicates low vacuum at 2.500 rpm.
(c) Disconnect the vacuum hose port R of the EGR vacuum modulator and connect port R directly to the air intake chamber with another hose.
(d) Check that the vacuum gauge indicates high vacuum at 2.500 rpm.

HINT: As a large amount of exhaust gas enters, the engine will misfire slightly.

7. Disconnect Toyota hand-held tester or OBD II scan tool
Remove vacuum gauge.
Remove the vacuum gauge and reconnect the vacuum hoses to the proper locations.




9. Inspect EGR valve.
(a) Apply vacuum directly to the EGR valve with the engine idle.
(b) Check that the engine runs rough or dies.
(c) Reconnect the vacuum hoses to the proper locations.
If no problem is found with this inspection, system is normal; otherwise inspect each part.
10. Cancel diagnostic trouble code.