Evaporative Emissions System: Testing and Inspection
INSPECTION1. VISUALLY INSPECT LINES AND CONNECTIONS
Look for loose connections, sharp bends or damage.
2. VISUALLY INSPECT FUEL TANK
Look for deformation, cracks or fuel leakage.
3. VISUALLY INSPECT FUEL TANK CAP
Check if the cap and/or gasket are deformed or damaged.
If necessary, repair or replace the cap.
4. INSPECT EVAP SYSTEM LINE
a. Warm up the engine and stop the engine. Allow the engine to warm up to normal operating temperature.
b. Install a vacuum gauge (EVAP control system test equipment vacuum gauge) to the EVAP service port on the purge line.
c. LEXUS Hand-Held Tester:
Forced driving of the VSV for the EVAP.
1. Connect a LEXUS hand-held tester to the DLC3.
2. Start the engine.
3. Push the LEXUS hand-held tester main switch ON.
4. Use the ACTIVE TEST mode on the LEXUS hand-held tester to operate the VSV for the EVAP
d. If you have no LEXUS Hand-Held Tester:
Forced driving of the VSV for the EVAP
1. Disconnect the VSV connector for the EVAP.
2. Connect the positive (+) and negative (-) leads from the battery to the VSV terminals for the EVAP.
3. Start the engine.
e. Check the vacuum at idle.
Vacuum: Maintain at 0.368 - 19.713 in.Hg (5 - 268 in.Aq) for over 5 seconds
HINT: If the vacuum does not change, you can conclude that the hose connecting the VSV to the service port has come loose or is blocked, or the VSV is malfunctioning.
f. LEXUS Hand-Held Tester:
Conclude forced driving of the VSV for the EVAP.
1. Stop the engine.
2. Disconnect the LEXUS hand-held tester from the DLC3.
g. If you have no LEXUS Hand-Held Tester:
Conclude forced driving of the VSV for the EVAP.
1. Stop the engine.
2. Disconnect the positive (+) and negative (-) leads from the battery from the VSV terminals for the EVAP
3. Connect the VSV connector for the EVAP
h. Disconnect the vacuum gauge from the EVAP service port on the purge line.
i. Connect a pressure gauge to the EVAP service port on the purge line.
j. Check the pressure.
1. Remove the screw and clip from the engine under cover as shown in the illustration.
2. Pull up the engine under cover, and close off the yellow marked position of the air drain hose with a hose clipper or similar instrument.
3. Add the pressure (13.5 - 15.5 in.Aq) from the EVAP service port.
Pressure: 2 minutes alter the pressure is added, the gauge should be over 7.7 - 8.8 in.Aq.
HINT: If you can't add pressure, you can conclude that the hose connecting the VSV-canister-fuel tank has slipped off or the VSV is open.
4. Check if the pressure decreases when the fuel tank cap is removed while adding pressure.
HINT: If the pressure does not decrease when the filler cap is removed, then you can conclude that the hose connecting the service port to the fuel tank is blocked, etc.
k. Disconnect the pressure gauge from the EVAP service port on the purge line.
l. Remove the hose clipper from the air drain hose.
m. Reinstall the screw and clip to the engine under cover.
5. REMOVE CHARCOAL CANISTER
6. VISUALLY INSPECT CHARCOAL CANISTER
Look for cracks or damage.
7. CHECK FOR CLOGGED FILTER, AND STUCK CHECK VALVE AND DIAPHRAGM
a. While holding port B closed, blow air (1.76 kPa (18 g/Sq.cm, 0.26 psi)) into port A and check that air flows from port D.
b. While holding port B and port D closed, blow air (1.76 kPa (18 g/Sq.cm, 0.26 psi)) into port A and check that air does not flow from port C.
c. Apply vacuum (2.11 kPa (16 mmHg, 0.62 in.Hg)) to port B, check that the vacuum does not decrease when port C is closed, and check that the vacuum decreases when port C is released.
d. While holding port C closed, apply vacuum (1.32 kPa (10 mmHg, 0.39 in.Hg)) to port A and check that air flows into port B.
If a problem is found, replace the charcoal canister.
8. REINSTALL CHARCOAL CANISTER
9. INSPECT VSV FOR EVAP
10. INSPECT VSV FOR VAPOR PRESSURE SENSOR
11. INSPECT VAPOR PRESSURE SENSOR