Component Tests and General Diagnostics

EGR SYSTEM INSPECTION
Except Model No. VZN17O - 4wd Long Wheel Base





1. CHECK 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 out to the atmospheric side.





2. INSTALL VACUUM GAUGE
Using a 3-way connector, connect a vacuum gauge to the hose between the EGR valve and VSV.
3. INSPECT SEATING OF EGR VALVE
Check that the engine starts and runs at idle.





4. CONNECT TERMINALS TE1 AND E1
Using SST, connect terminals TE1 and E1 of the DLC1. SST 09843-18020





5. INSPECT VSV OPERATION WITH COLD ENGINE
(a) The engine coolant temperature should be below 450°C (113°F).
(b) Check that the vacuum gauge indicates zero at 2,800 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 80°C (176°F).
(b) Check that the vacuum gauge indicates low vacuum at 2,800 rpm.
(c) Disconnect the vacuum hose from port R of the EGR vacuum modulator and connect port R directly to the intake manifold with another hose.
(d) Check that the vacuum gauge indicates high vacuum at 3,500 rpm.

HINT: As exhaust gas is increasingly recirculated, the engine will start to misfire.

7. DISCONNECT TERMINALS TE1 AND E1 Remove the SST from the DLC1. SST 09843-18020
8. REMOVE VACUUM GAUGE
Remove the vacuum gauge and reconnect the vacuum hoses to their 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 their proper locations.
IF NO PROBLEM IS FOUND DURING THIS INSPECTION, SYSTEM IS NORMAL; OTHERWISE INSPECT EACH PART