Exhaust Gas Recirculation: Testing and Inspection

1. INSPECT AND CLEAN FILTER IN EGR VACUUM MODULATOR





- Remove the cap and filter.
- Check the filter for contamination or damage.
- Using compressed air, clean the filter.
- 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 VACUUM SWITCHING VALVE (VSV) OPERATION WITH COLD ENGINE.
- The engine coolant temperature should be below 47°C (117°F).
- Check that the vacuum gauge indicates zero at 2,500 rpm.
- Check that the EGR pipe is not hot.
6. INSPECT OPERATION OF VSV AND EGR VACUUM MODULATOR WITH HOT ENGINE.
- Warm up the engine to above 53°C (127°F).





- Check that the vacuum gauge indicates low vacuum at 2,500 rpm.
- Disconnect the vacuum hose port R of the EGR vacuum modulator and connect port R directly to the air intake chamber with another hose.
- 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
8. REMOVE VACUUM GAUGE.
- Remove the vacuum gauge, and reconnect the vacuum hoses to the proper locations.
9. INSPECT EGR VALVE.





- Apply vacuum directly to the EGR valve with the engine idle.
- Check that the engine runs rough or dies.
- 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.