Part 1
3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: EVAP System
- EVAP System
RELATED DTCS
If any EVAP system DTCs are set, the malfunctioning area can be determined using the table below.
NOTICE:
If the 0.02 inch reference pressure difference between the first and second checks is greater than the specification, the DTCs corresponding to the reference pressure (P043E, P043F, P0441, P0455, P0456, P2401 and P2420) will all be stored.
DESCRIPTION
NOTICE:
In this vehicle's EVAP system, turning ON the vent valve does not seal off the EVAP system. To check for leaks in the EVAP system, disconnect the air inlet vent hose and apply pressure from the atmosphere side of the canister.
While the engine is running, if a predetermined condition (closed loop, etc.) is met, the purge VSV is opened by the ECM and stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the duty cycle ratio of the purge VSV to control purge flow volume.
The purge flow volume is also determined by the intake manifold pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that the purge flow is maintained when the negative pressure (vacuum) is applied to the canister.
The following two monitors run to confirm appropriate EVAP system operation.
1. Key-off monitor
This monitor checks for Evaporative Emission (EVAP) system leaks and canister pump module malfunctions. The monitor starts 5 hours* after the ignition switch is turned OFF. More than 5 hours are required to allow the fuel to cool down to stabilize the Fuel Tank Pressure (FTP), thus making the EVAP system monitor more accurate.
The leak detection pump creates negative pressure (vacuum) in the EVAP system and the pressure is measured. Finally, the ECM monitors for leaks from the EVAP system and malfunctions in both the canister pump module and purge VSV based on the EVAP pressure.
HINT
*: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned OFF, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned OFF, the monitor check starts 2.5 hours later.
2. Purge flow monitor
The purge flow monitor consists of the two monitors. The 1st monitor is conducted every time and the 2nd monitor is conducted if necessary.
* The 1st monitor
* While the engine is running and the purge Vacuum Switching Valve (VSV) is ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor.
* The 2nd monitor
* The vent valve is turned OFF (open) and the EVAP pressure is measured. If negative pressure is not created, the ECM interprets this as the purge VSV being stuck closed, illuminates the MIL and sets DTC P0441 (2 trip detection logic).
Atmospheric pressure check:
In order to ensure reliable malfunction detection, the variation between the atmospheric pressures, before and after conduction of the purge flow monitor, is measured by the ECM.
WIRING DIAGRAM
INSEPCTION PROCEDURE
NOTICE:
* The Techstream is required to conduct the following diagnostic troubleshooting procedure.
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT
* Using the Techstream monitor results enable the EVAP system to be confirmed.
* Read freeze frame data using the Techstream. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
1. CONFIRM DTC
(a) Turn the ignition switch OFF and wait for 10 seconds.
(b) Turn the ignition switch to ON.
(c) Turn the ignition switch OFF and wait for 10 seconds.
(d) Connect the Techstream to the DLC3.
(e) Turn the ignition switch to ON.
(f) Enter the following menus: Powertrain / Engine / Trouble Codes.
(g) Confirm DTCs and freeze frame data.
If any EVAP system DTCs are set, the malfunctioning area can be determined using the table below.
NOTICE:
If the reference pressure difference between the first and second checks is greater than the specification, the DTCs corresponding to the reference pressure (P043E, P043F, P0441, P0455, P0456, P2401 and P2420) will all be stored.
NEXT -- Continue to next step.
2. PERFORM EVAPORATIVE SYSTEM CHECK (AUTOMATIC MODE)
NOTICE:
* In the Evaporative System Check (Automatic Mode), the series of 5 Evaporative System Check steps are performed automatically. It takes a maximum of approximately 19 minutes.
* Do not perform the Evaporative System Check when the fuel tank is more than 90% full because the cut-off valve may be closed, making the leak check of the fuel tank not possible.
* Do not run the engine in this step.
* When the temperature of the fuel is 35°C (95°F) or more, a large amount of vapor forms and any check results become inaccurate. When performing the Evaporative System Check, keep the temperature below 35°C (95°F).
(a) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.
(b) Enter the following menus: Powertrain / Engine / Utility / Evaporative System Check / Automatic Mode.
(c) After the Evaporative System Check is completed, check for pending DTCs by entering the following menus: Powertrain / Engine / Trouble Codes / Pending.
HINT
If no pending DTC is displayed, perform the Monitor Confirmation after the repair is completed. After this confirmation, check for pending DTCs. If no DTC is displayed, the EVAP system is normal.
NEXT -- Continue to next step.
3. PERFORM EVAPORATIVE SYSTEM CHECK (MANUAL MODE)
NOTICE:
* In the Evaporative System Check (Manual Mode), the series of 5 Evaporative System Check steps are performed manually.
* Do not perform the Evaporative System Check when the fuel tank is more than 90% full because the cut-off valve may be closed, making the leak check of the fuel tank not possible.
* Do not run the engine in this step.
* When the temperature of the fuel is 35°C (95°F) or more, a large amount of vapor forms and any check results become inaccurate. When performing the Evaporative System Check, keep the temperature below 35°C (95°F).
(a) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.
(b) Enter the following menus: Powertrain / Engine / Utility / Evaporative System Check / Manual Mode.
NEXT -- Continue to next step.
4. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 1/5)
(a) Check the EVAP pressure in step 1/5.
Result:
HINT
*: The DTCs related to the EVAP system are displayed on the Techstream when checking.
B -- REPLACE CANISTER ASSEMBLY
A -- Continue to next step.
5. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 1/5 TO 2/5)
(a) Check the EVAP pressure in step 1/5 and 2/5.
Result:
HINT
* *: The DTCs related to the EVAP system are displayed on the Techstream when checking.
* The first reference pressure. is the value determined in step 2/5.
B -- PERFORM ACTIVE TEST USING TECHSTREAM (FOR CANISTER PUMP MODULE [LEAK DETECTION PUMP])
A -- Continue to next step.
6. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 2/5)
HINT
Make a note of the pressures checked in the steps below.
(a) Check the EVAP pressure 4 seconds after the leak detection pump is activated*.
### ptxt ### *: The leak detection pump begins to operate as step 1/5 proceeds to step 2/5.
(b) Check the EVAP pressure again when it has stabilized. This pressure is the reference pressure.
Result:
HINT
*: The DTCs related to the EVAP system are displayed on the Techstream when checking.
D -- PERFORM ACTIVE TEST USING TECHSTREAM (FOR VENT VALVE)
C -- REPLACE CANISTER ASSEMBLY
B -- PERFORM EVAPORATIVE SYSTEM CHECK (STEP 3/5)
A -- Continue to next step.
7. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 2/5 TO 3/5)
(a) Check the EVAP pressure in step 3/5.
Result:
HINT
*: The DTCs related to the EVAP system are displayed on the Techstream when checking.
C -- REPLACE CANISTER ASSEMBLY
B -- PERFORM ACTIVE TEST USING TECHSTREAM (FOR VENT VALVE)
A -- Continue to next step.
8. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 3/5)
(a) Wait until the EVAP pressure change is less than 0.1 kPa (0.75 mmHg) for 30 seconds.
(b) Measure the EVAP pressure and record it.
HINT
A few minutes are required for the EVAP pressure to become saturated. When there is little fuel in the fuel tank, it takes up to 15 minutes (900 seconds).
NEXT -- Continue to next step.
9. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 4/5)
(a) Check the EVAP pressure in step 4/5.
Result:
HINT
*: The DTCs related to the EVAP system are displayed on the Techstream when checking.
C -- PERFORM ACTIVE TEST USING TECHSTREAM (PURGE VSV)
B -- CHECK PURGE LINE HOSE (PURGE VSV - INTAKE MANIFOLD)
A -- Continue to next step.
10. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 5/5)
(a) Check the EVAP pressure in step 5/5.
(b) Compare the EVAP pressure in step 3/5 and the second reference pressure (step 5/5).
Result:
HINT
*: The DTCs related to the EVAP system are displayed on the Techstream when checking.
B -- PERFORM ACTIVE TEST USING TECHSTREAM (PURGE VSV)
A -- REPAIR OR REPLACE PARTS AND COMPONENTS INDICATED BY OUTPUT DTCS
11. PERFORM EVAPORATIVE SYSTEM CHECK (STEP 3/5)
(a) Check the EVAP pressure in step 3/5.
Result:
HINT
* *: The DTCs related to the EVAP system are displayed on the Techstream when checking.
* The first reference pressure is the value determined in step 2/5.
B -- PERFORM ACTIVE TEST USING TECHSTREAM (FOR CANISTER PUMP MODULE [LEAK DETECTION PUMP])
A -- REPLACE CANISTER ASSEMBLY
12. PERFORM ACTIVE TEST USING TECHSTREAM (PURGE VSV)
(a) Enter the following menus: Powertrain / Engine / Active Test / Activate the VSV for EVAP Control.
(b) Disconnect the hose (connected to the canister) from the purge VSV.
(c) Start the engine.
(d) Using the Techstream, turn the purge VSV OFF.
(e) Use your finger to confirm that the purge VSV has no suction.
(f) Using the Techstream, turn the purge VSV ON.
(g) Use your finger to confirm that the purge VSV has suction.
Result:
