Part 1
2AZ-FXE ENGINE CONTROL: 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 reference pressure difference between the first and second checks is greater than the specification, all the DTCs relating to the reference pressure (P043E, P043F, P2401, P2402 and P2419) are stored.
DESCRIPTION
Text in Illustration
HINT
The canister pressure sensor, the leak detection pump and the vent valve are built into the canister pump module.
Text in Illustration
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 atmospheric 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 hybrid vehicle control ECU and stored fuel vapors in the canister are purged into the intake manifold.
The purge flow volume is affected by the intake manifold pressure (vacuum). To control the purge volume, the hybrid vehicle control ECU changes the duty cycle ratio of the purge VSV based on the pressure (vacuum) in the intake manifold. The hybrid vehicle control ECU uses values received from the manifold absolute pressure sensor to monitor the pressure (vacuum) in the intake manifold.
Atmospheric pressure is allowed into the canister through the vent valve to ensure that the purge flow is maintained when negative pressure (vacuum) is applied to the canister.
The following two monitors run to confirm the appropriate EVAP system operation.
1. Key-off monitor
This monitor checks for EVAP (evaporative emission) system leaks and canister pump module malfunctions. The monitor starts 5 hours* after the power switch is turned off. At least 5 hours are required for the fuel to cool down to stabilize the EVAP pressure, 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 hybrid vehicle control ECU 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 power 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 power switch is turned off, the monitor check starts 2.5 hours later.
2. Purge flow monitor
The purge flow monitor consists of the 2 monitors. The 1st monitor is conducted every time and the 2nd monitor is activated if necessary.
* The 1st monitor
* While the engine is running and the purge VSV (Vacuum Switching Valve) is on (open), the hybrid vehicle control ECU monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the hybrid vehicle control ECU begins the 2nd monitor.
* The 2nd monitor
* The vent valve is turned off (open) and the EVAP pressure is measured. If the variation in the pressure is less than 0.5 kPa-g (3.75 mmHg-g), the hybrid vehicle control ECU interprets this as the purge VSV being stuck closed, and 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 the purge flow monitor, is measured by the hybrid vehicle control ECU.
Text in Illustration
MONITOR RESULT
Refer to Checking Monitor Status Mode 6 Data.
CONFIRMATION DRIVING PATTERN
HINT
After a repair, check Monitor Status by performing the Key-off Monitor Confirmation and Purge Flow Monitor Confirmation described below.
1. KEY-OFF MONITOR CONFIRMATION
(a) Preconditions
The monitor will not run unless:
* The vehicle has been driven for 10 minutes or more (in a city area or on a freeway).
* The fuel tank is less than 90% full.
* The altitude is less than 7875 ft. (2400 m).
* The engine coolant temperature is between 4.4°C and 35°C (40°F and 95°F).
* The intake air temperature is between 4.4°C and 35°C (40°F and 95°F).
* The vehicle remains stationary (the vehicle speed is 0 mph [0 km/h]).
(b) Monitor Conditions
* Allow the engine to idle for at least 5 minutes.
* Turn the power switch off and wait for 6 hours (8 or 10.5 hours).
HINT
Do not start the engine until the Monitor Status has been checked. If the engine is started, the steps described above must be repeated.
(c) Monitor Status
* Connect the Techstream to the DLC3.
* Turn the power switch on (IG).
* Turn the Techstream on.
* Enter the following menus: Powertrain / Engine and ECT / Monitor / Evaporative System.
* Check the Monitor Status displayed on the Techstream.
HINT
If Incomplete is displayed, the monitor did not complete. Make sure that the preconditions have been met, and perform the Monitor Conditions again.
2. PURGE FLOW MONITOR CONFIRMATION (P0441)
HINT
Perform this monitor confirmation after the Key-off Monitor Confirmation shows Complete.
(a) Preconditions
The monitor will not run unless:
* The vehicle has been driven for 10 minutes or more (in a city area or on a freeway).
* The engine coolant temperature is between 4.4°C and 35°C (40°F and 95°F).
* The intake air temperature is between 4.4°C and 35°C (40°F and 95°F).
(b) Monitor Conditions
* Release the pressure from the fuel tank by removing and reinstalling the fuel cap.
* Warm the engine up until the engine coolant temperature reaches more than 75°C (167°F).
* Increase the engine speed to 3000 rpm once.
* Allow the engine to idle and turn the the A/C switch on for 1 minute.
(c) Monitor Status
* Turn the power switch off (if on (IG) or if the engine is running).
* Connect the Techstream to the DLC3.
* Turn the power switch on (IG).
* Turn the Techstream on.
* Enter the following menus: Powertrain / Engine and ECT / Monitor / Evaporative System.
* Check the Monitor Status displayed on the Techstream.
HINT
If Incomplete is displayed, the monitor did not complete. Make sure that the preconditions have been met, and perform the Monitor Conditions again.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
* Inspect the fuses for circuits related to this system before performing the following inspection procedure.
* The Techstream is required to conduct the following diagnostic troubleshooting procedure.
HINT
* Using Techstream monitor results enables the EVAP (evaporative emission) system to be confirmed.
* Read freeze frame data using the Techstream. The hybrid vehicle control ECU records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.
* (kPa-a [mmHg-a]) denotes the absolute pressure.
* (kPa-g [mmHg-g]) denotes the gauge pressure (relative pressure).
* On the Techstream, convert the unit of measurement according to the inspection procedure.
PROCEDURE
1. CONFIRM DTC
(a) Turn the power switch off and wait for 10 seconds.
(b) Turn the power switch on (IG).
(c) Turn the power switch off and wait for 10 seconds.
(d) Connect the Techstream to the DLC3.
(e) Turn the power switch on (IG).
(f) Turn the Techstream on.
(g) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(h) Confirm DTCs and freeze frame data.
If any EVAP system DTCs are set, the malfunctioning area can be determined using the following table.
NOTICE:
If the reference pressure difference between the first and second checks is greater than the specification, all the DTCs relating to the reference pressure (P043E, P043F, P2401, P2402 and P2419) are stored.
NEXT -- Continue to next step.
2. PERFORM EVAPORATIVE SYSTEM CHECK (AUTO OPERATION)
NOTICE:
* In the Evaporative System Check (Automatic Mode), a series of 5 steps is performed automatically by the Techstream. It takes a maximum of approximately 18 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 fuel tank leak check unavailable.
* Do not run the engine during this operation.
* 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 fuel temperature below 35°C (95°F).
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs DTC Check / Clear.
(e) Enter the following menus: Powertrain / Engine and ECT / Utility / Evaporative System Check / Automatic Mode.
(f) After the Evap System Check is completed, check for pending DTCs by entering the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
HINT
If no pending DTCs are displayed, perform the Monitor Confirmation (see "Diagnostic Help" menu). After this confirmation, check for pending DTCs. If no DTCs are displayed, the EVAP system is normal.
NEXT -- Continue to next step.
3. PERFORM EVAPORATIVE SYSTEM CHECK (MANUAL OPERATION)
NOTICE:
* In the Evaporative System Check (Manual Mode), perform the series of 5 Evaporative System Check steps manually using the Techstream.
* 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 fuel tank leak check unavailable.
* Do not run the engine during this operation.
* 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 fuel temperature below 35°C (95°F).
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs DTC Check / Clear.
(e) Enter the following menus: Powertrain / Engine and ECT / 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:
(b) *: These DTCs are already present in the hybrid vehicle control ECU when the vehicle arrives and are confirmed in the "Confirm DTC" procedure above.
B -- REPLACE CANISTER
A -- Continue to next step.