EMISSION CONTROL SYSTEM(w/ Canister Pump Module)


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly) Detects the internal pressure of the fuel tank assembly and sends a signal to the ECM assembly.
    Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) This valve opens or closes in accordance with a signal provided by the ECM assembly, in order to seal the fuel tank assembly or release its internal pressure.
    Fuel Lid Lock with Motor Assembly

    • The fuel lid lock with motor assembly consists of a built-in motor that opens the fuel lid via a linkage.

    • If the fuel lid lock with motor assembly malfunctions, the fuel lid can be opened manually by pulling on the emergency opener that is provided on the fuel lid lock with motor assembly.
    Fuel Lid Lock with Motor Assembly Fuel Lid Courtesy Switch Whether the fuel lid is open or closed can be determined by the state (on or off) of this switch.
    Combination Meter Assembly Multi-information Display The multi-information display displays warnings in accordance with a signal from the ECM assembly that has judged that the fuel lid is open.
    Canister Contains activated charcoal to absorb the vapors that are created in the fuel tank assembly as well as during refueling.
    Purge VSV Opens in accordance with the signals from the ECM assembly when the system is purging in order to send the fuel vapors that were absorbed by the canister into the intake manifold. During the system monitoring mode, this valve controls the vacuum applied to the fuel tank assembly.
    Canister Pump Module Leak Detection Pump Applies vacuum to the evaporative emission system in accordance with the signals from the ECM assembly.
    Vent Valve Opens and closes the fresh air line in accordance with the signals from the ECM assembly.
    Canister Pressure Sensor Detects the pressure in the evaporative emission system and sends a signal to the ECM assembly.
    ECM Assembly

    • The ECM assembly determines the results of the canister pump module's system leak check, effects purge control through the fuel vapor-containment valve (fuel tank solenoid main valve assembly) and the purge VSV, and controls the internal pressure of the fuel tank assembly.

    • The ECM assembly monitors the system for any leaks and outputs a DTC if a malfunction is found.

  2. SYSTEM CONTROL


    1. Fuel Vapor-containment System


      1. Parked (Power Switch Mode Off)


        • The ECM assembly seals the fuel vapors in the fuel tank assembly by closing the fuel vapor-containment valve (fuel tank solenoid main valve assembly). At this time, if the internal pressure of the fuel tank assembly increases to a level above the specified pressure of the fuel outlet valve located in the fuel vapor-containment valve (fuel tank solenoid main valve assembly), the fuel outlet valve opens to release the internal pressure of the fuel tank assembly. This prevents the internal pressure in the fuel tank assembly from increasing abnormally.

          A01R1Z8C01
          *1 ECM Assembly *2 Fuel Outlet Valve (Closed)
          *3 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Closed) *4 Canister

      2. Refueling Wait


        • When the lid opener switch is operated, the ECM assembly opens the fuel vapor-containment valve (fuel tank solenoid main valve assembly), allowing the fuel vapors to be absorbed by the canister and reducing the pressure in the fuel tank assembly. The fuel lid will not open unless the internal pressure of the fuel tank assembly decreases to a level close to atmospheric pressure. In addition, the multi-information display will show the "PLEASE WAIT NOW OPENING".

          A01R1XBC01
          *1 ECM Assembly *2 Fuel Lid Opener Switch (On)
          *3

          Fuel Lid Lock with Motor Assembly


          • Fuel Lid Courtesy Switch

          		 *4 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
          *5 Fuel Outlet Valve (Closed) *6 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Open)
          *7

          Combination Meter Assembly


          • Multi-information Display

          		 *8 Canister

      3. Refueling Ready


        • When the internal pressure of the fuel tank assembly decreases to a level close to atmospheric pressure, the ECM assembly opens the fuel lid. At this time, the multi-information display will show "REFUEL READY". Because the ECM assembly keeps the fuel vapor-containment valve (fuel tank solenoid main valve assembly) open during refueling, the fuel vapors that are created during refueling pass through the fuel vapor-containment valve (fuel tank solenoid main valve assembly) and are absorbed by the canister. When the fuel lid is closed after refueling, the fuel vapor-containment valve (fuel tank solenoid main valve assembly) closes in order to seal the fuel tank assembly.

        • If 30 minutes elapse after the fuel lid is opened, the ECM assembly closes the fuel vapor-containment valve (fuel tank solenoid main valve assembly) to seals the fuel tank assembly in order to prevent the fuel vapors from escaping, even if the fuel lid is not closed.

          A01R2HDC01
          *1 ECM Assembly *2 Fuel Lid Opener Switch (On)
          *3

          Fuel Lid Lock with Motor Assembly (Open)


          • Fuel Lid Courtesy Switch

          		 *4 Canister Filter
          *5 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly) *6 Fuel Outlet Valve (Closed)
          *7 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Open) *8

          Combination Meter Assembly


          • Multi-information Display
          *9 Canister - -

      4. Fuel Lid Open Warning


        • If one of the conditions listed below is met while the fuel lid is open, the ECM assembly will show a "CLOSE FUEL LID" warning message on the multi-information display to warn the driver.


          • The vehicle speed is higher than 50 km/h (31 mph).

          • The vehicle has traveled more than 1 km (0.6 mile).

          • 30 minutes have elapsed since the fuel vapor-containment valve (fuel tank solenoid main valve assembly) was opened.

            A01R2KWC01
            *1 ECM Assembly *2

            Fuel Lid Lock with Motor Assembly (Open)


            • Fuel Lid Courtesy Switch
            *3 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly) *4 Fuel Outlet Valve (Closed)
            *5 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Closed) *6

            Combination Meter Assembly


            • Multi-information Display
            *7 Canister - -

    2. Purge flow Control


      1. When the engine has reached predetermined parameters (closed loop, engine coolant temperature above 70°C (162°F), etc.), stored fuel vapors are purged from the canister whenever the purge VSV is opened by the ECM assembly. The ECM assembly changes the duty ratio cycle of the purge VSV thus controlling purge flow volume. The purge flow volume depends on the intake manifold pressure and the duty ratio cycle of the purge VSV. Atmospheric pressure is allowed into the canister to ensure that purge flow is constantly maintained whenever purge vacuum is applied to the canister.

      2. Due to the adoption of a fuel vapor-containment system, purge flow control occurs following 2 patterns, depending on the internal pressure of the fuel tank assembly.

      3. If the internal pressure in the fuel tank assembly is near atmospheric pressure, the ECM assembly will not open the fuel vapor-containment valve (fuel tank solenoid main valve assembly) even if the purge VSV is open. At this time, the fuel vapors that are absorbed in the canister are drawn inside the engine and burned.

        A01R2CFC01
        *1 ECM Assembly *2 Purge VSV (Open)
        *3 Canister Filter *4 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
        *5 Fuel Outlet Valve (Closed) *6 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Closed)
        *7 Canister - -
        *a To Intake Manifold *b Purge Line
        *c Fresh Air Line - -

      4. If the internal pressure in the fuel tank assembly is high and the purge valve is open, the ECM assembly opens the fuel vapor-containment valve (fuel tank solenoid main valve assembly) in order to release the pressure from the fuel tank assembly. At this time, the fuel vapors that are absorbed in the canister are drawn inside the engine by intake vacuum and burned.

        A01R26PC01
        *1 ECM Assembly *2 Purge VSV (Open)
        *3 Canister Filter *4 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
        *5 Fuel Outlet Valve (Closed) *6 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Open)
        *7 Canister - -
        *a To Intake Manifold *b Purge Line
        *c Fresh Air Line - -

    3. EVAP Leak Check


      1. The following are the typical conditions necessary to enable an evaporative emission leak check:

        Typical Enabling Conditions

        • 5 hours have elapsed after the engine has been turned off*.

        • Altitude: Below 2400 m (8000 ft.)

        • Auxiliary Battery Voltage: 10.5 V or higher

        • Power Switch: Off

        • Engine Coolant Temperature: Between 4.4 and 35°C (40 and 95°F)

        • Intake Air Temperature: Between 4.4 and 35°C (40 and 95°F)

        *: If the engine coolant temperature does not drop below 35°C (95°F), this time is extended to 7 hours. After that, if the temperature is not less than 35°C (95°F), the time is extended to 9.5 hours.

        Tech Tips

        The canister pump module performs the fuel evaporative emission leak check. This check is done approximately 5 hours after the engine is turned off. A sound may be heard coming from underneath the luggage compartment for several minutes. This sound does not indicate a malfunction.

      2. The ECM assembly performs evaporative emission leak checks using 2 types of judgment methods.


        • When the internal pressure in the fuel tank assembly is equal to atmospheric pressure:


          • The ECM assembly actuates the leak detection pump to introduce a vacuum into the EVAP system pipes and the canister, in order to check for leaks and check the function of parts.

          • The ECM assembly actuates the leak detection pump and opens the fuel vapor-containment valve (fuel tank solenoid main valve assembly) to introduce a vacuum into the fuel tank assembly, in order to check the fuel tank assembly for leaks and determine whether the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is stuck closed.

            Figure 1. When Fuel Tank Internal Pressure Equals Atmospheric Pressure

            A01R2CXE01
            Order Operation Description Time
            1) Atmospheric Pressure Measurement The ECM assembly turns the vent valve off (vent) and measures evaporative emission control system pressure to memorize the atmospheric pressure. 60 sec.
            2) First Reference Pressure Measurement The leak detection pump creates negative pressure (vacuum) through the reference orifice. The ECM assembly uses this as the first reference pressure. 360 sec.
            3) EVAP Leak Check The leak detection pump creates negative pressure (vacuum) to check for leaks in the canister. If the stabilized pressure is larger than the first reference pressure, the ECM assembly determines that the evaporative emission control system has a leak. If the pressure does not stabilize within 15 minutes, the ECM assembly cancels evaporative emission control system monitoring. Within 15 min.
            4) Purge VSV Monitor The ECM assembly opens the purge VSV and monitors the vacuum created by the leak detection pump. If the pressure change is large (the pressure changes from vacuum to near atmospheric pressure), the ECM assembly determines that the purge VSV is functioning normally. 10 sec.
            5) Second Reference Pressure Measurement First, the leak detection pump creates negative pressure (vacuum) through the reference orifice. The ECM assembly uses this as the second reference pressure. Then, the ECM assembly turns the leak detection pump off and measures the pressure to memorize atmospheric pressure. 60 sec. and 5 sec.
            6) Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) Stuck Closed Judgment and Fuel Tank Leak Judgment When the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is open, the leak detection pump creates a negative pressure (vacuum) in the fuel tank assembly and the ECM assembly measures the pressure at this time. Within 15 min.
            7) Third Reference Pressure Measurement The leak detection pump creates negative pressure (vacuum) through the reference orifice. The ECM assembly uses this as the third reference pressure. 60 sec.
            8) Final Check The ECM assembly measures atmospheric pressure and then records the monitor result. -

        • When the internal pressure in the fuel tank assembly is higher or lower than atmospheric pressure:


          • If the internal pressure of the fuel tank assembly is high or low, the ECM assembly determines that there are no leaks in the fuel tank assembly, based on the holding state of the internal pressure in the fuel tank assembly.

          • The ECM assembly actuates the leak detection pump to introduce a vacuum into EVAP system pipes and the canister in order to check for leaks and check the function of parts.

          • With the leak detection pump stopped, the ECM assembly opens the fuel vapor-containment valve (fuel tank solenoid main valve assembly) to introduce the pressure from the fuel tank assembly into EVAP system pipes and the canister, in order to determine whether the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is stuck closed.

            Figure 2. When Fuel Tank Internal Pressure is High or Low

            A01R2IYE01
            Order Operation Description Time
            1) Atmospheric Pressure Measurement The ECM assembly turns the vent valve off (vent) and measures evaporative emission control system pressure to memorize the atmospheric pressure. 60 sec.
            2) First Reference Pressure Measurement The leak detection pump creates negative pressure (vacuum) through the reference orifice. The ECM assembly uses this as the first reference pressure. 360 sec.
            3) EVAP Leak Check The leak detection pump creates negative pressure (vacuum) to check for leaks in the canister. If the stabilized pressure is larger than the first reference pressure, the ECM assembly determines that the evaporative emission control system has a leak. If the leak detection pump pressure does not stabilize within 15 minutes, the ECM assembly cancels evaporative emission control system monitoring. Within 15 min.
            4) Purge VSV Monitor The ECM assembly opens the purge VSV and monitors the vacuum created by the leak detection pump. If the pressure change is large (the pressure changes from vacuum to near atmospheric pressure), the ECM assembly determines that the purge VSV valve is functioning normally. 10 sec.
            5) Second Reference Pressure Measurement First, the leak detection pump creates vacuum through the reference orifice. The ECM assembly uses this as the second reference pressure. Then, the ECM assembly turns the leak detection pump off and measures the pressure to memorize atmospheric pressure. Following this, the vent valve is switched to the on position (vent). 60 sec. and 5 sec.
            6) Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) Stuck Closed Judgment Using the pre-existing pressure or vacuum in the fuel tank assembly, the ECM assembly monitors the pressure at the time the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is opened. 0.1 sec.
            7) Final Check The ECM assembly measures atmospheric pressure and then records the monitor result. -

      3. Atmospheric Pressure Measurement


        1. When the power switch is turned off, the purge VSV and the fuel vapor-containment valve (fuel tank solenoid main valve assembly) are off (closed). Therefore, atmospheric pressure is introduced into the canister.

        2. The ECM assembly measures the atmospheric pressure through the signals provided by the canister pressure sensor.

        3. If the measurement value is out of standard, the ECM assembly actuates the leak detection pump in order to monitor the pressure changes.

        4. If the ECM assembly does not detect pressure changes, it stops the leak check and stores DTC (Diagnostic Trouble Codes) P0451 in its memory.

          A01R2FMC01
          *1 ECM Assembly *2 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
          *3 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Closed) *4 Canister
          *5 Purge VSV (Closed) *6 Leak Detection Pump (Off)
          *7 Canister Pressure Sensor *8 Vent Valve (Vent Position)
          *9 Canister Pump Module - -
          *a Atmosphere - -

        5. The atmospheric pressure is measured at the following timing:

          A01R2ATE05

      4. First Reference Pressure Measurement


        1. The ECM assembly turns the vent valve off (vent), introducing atmospheric pressure into the canister, and actuates the leak detection pump, in order to create negative pressure.

        2. At this time, the pressure will not decrease beyond a certain level due to the atmospheric pressure that enters through the reference orifice.

        3. The ECM assembly compares the logic value and this pressure and stores the measured pressure as the first reference pressure.

        4. If the measurement value is below the standard (too much vacuum), the ECM assembly determines that the reference orifice is clogged and stores DTC P043E in its memory.

        5. If the measurement value is above the standard (pressure is too high, not enough vacuum), the ECM assembly determines that a high flow rate of pressure is passing through the reference orifice and stores DTC P043F, P2401 and P2402 in memory.

          A01R1VRC01
          *1 ECM Assembly *2 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
          *3 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Closed) *4 Canister
          *5 Purge VSV (Closed) *6 Leak Detection Pump (On)
          *7 Canister Pressure Sensor *8 Vent Valve (Vent Position)
          *9 Canister Pump Module - -
          *a Atmosphere - -

        6. The timing of the first reference pressure measurement is as follows:

          A01R2G0E04

      5. EVAP Leak Check


        1. While actuating the leak detection pump, the ECM assembly turns the vent valve on (closes the vent) in order to introduce a vacuum into the canister (The fuel vapor-containment valve (fuel tank solenoid main valve assembly) is closed as shown below).

        2. When the pressure in the system stabilizes, the ECM assembly compares this pressure and the first reference pressure in order to determine if a leak is occurring.

        3. If the detection value is below the first reference pressure, the ECM assembly determines that there is no leak.

        4. If the detection value is above the first reference pressure and near atmospheric pressure, the ECM assembly determines that there is a large leak and stores DTC P1421 in its memory.

        5. If the detection value is above the first reference pressure and still below atmospheric pressure, the ECM assembly determines that there is a small leak and stores DTC P1420 in its memory.

        6. When the fuel tank internal pressure equals atmospheric pressure, if there is fluctuation in the fuel tank pressure sensor (vapor pressure sensor assembly) value, the ECM assembly determines that the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is stuck open and stores DTC P2450 in memory.

          A01R1X8C01
          *1 ECM Assembly *2 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
          *3 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Closed) *4 Canister
          *5 Purge VSV (Closed) *6 Leak Detection Pump (On)
          *7 Canister Pressure Sensor *8 Vent Valve (Vent Closed)
          *9 Canister Pump Module - -
          *a Atmosphere - -

        7. The timing of the EVAP leak check is as follows:

          A01R2JIE04

      6. Purge VSV Monitor


        1. After completing an EVAP leak check, the ECM assembly turns the purge VSV on (open) with the leak detection pump actuated, and introduces atmospheric pressure into the canister from the intake manifold.

        2. If the pressure change at this time is within the normal range, the ECM assembly determines the condition to be normal.

        3. If the pressure change is out of the normal range, the ECM assembly will stop the purge VSV monitor and stores DTC P0441 in memory.

          A01R24NC01
          *1 ECM Assembly *2 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
          *3 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Closed) *4 Canister
          *5 Purge VSV (Open) *6 Leak Detection Pump (On)
          *7 Canister Pressure Sensor *8 Vent Valve (Vent Closed)
          *9 Canister Pump Module - -
          *a Atmosphere - -

        4. The timing of the purge VSV monitoring is as follows:

          A01R2Q3E04

      7. Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) Stuck Closed Judgment and Fuel Tank Leak Check


        1. When Fuel Tank Internal Pressure Equals Atmospheric Pressure


          1. The ECM assembly actuates the leak detection pump, and turns on the vent valve (vent is closed) and the fuel vapor-containment valve (fuel tank solenoid main valve assembly) (valve opens), in order to introduce a vacuum into the fuel tank assembly, pipes, and canister.

          2. When the pressure in the system stabilizes, the ECM assembly compares this pressure and the first reference pressure in order to determine if a leak is occurring.

          3. If the detection value is below the first reference pressure, the ECM assembly determines that there is no leak.

          4. If the detection value is above the first reference pressure and near atmospheric pressure, the ECM assembly determines that there is a large leak and stores DTC P1423 in its memory.

          5. If the detection value is above the first reference pressure and still below atmospheric pressure, the ECM assembly determines that there is a small leak and stores DTC P1422 in its memory.

          6. At this time, if there is no fluctuation in the fuel tank pressure sensor (vapor pressure sensor assembly) value, the ECM assembly determines that the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is stuck closed and stores DTC P2451 in memory.

            A01R2MZC01
            *1 ECM Assembly *2 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
            *3 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Open) *4 Canister
            *5 Purge VSV (Closed) *6 Leak Detection Pump (On)
            *7 Canister Pressure Sensor *8 Vent Valve (Vent Closed)
            *9 Canister Pump Module - -
            *a Atmosphere - -

          7. The timing of the fuel tank leak check is as follows:

            A01R2RBE05

        2. When Fuel Tank Internal Pressure is Higher or Lower than Atmospheric Pressure


          1. If the internal pressure in the fuel tank assembly is high or low, the ECM assembly determines that there is no leak in the fuel tank assembly. Thus, it is only necessary to determine if the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is stuck closed, without performing a fuel tank leak check.

          2. With the leak detection pump stopped, the ECM assembly turns the fuel vapor-containment valve (fuel tank solenoid main valve assembly) on (the valve opens) to introduce the internal pressure of the fuel tank assembly into the pipes and the canister.

          3. The ECM assembly measures the atmospheric pressure through the signals provided by the canister pressure sensor.

          4. If the value detected by the canister pressure sensor stays within a specified range, the ECM assembly determines that the fuel vapor-containment valve (fuel tank solenoid main valve assembly) is stuck closed and stores DTC P2451 in memory.

            A01R25QC01
            *1 ECM Assembly *2 Fuel Tank Pressure Sensor (Vapor Pressure Sensor Assembly)
            *3 Fuel Vapor-containment Valve (Fuel Tank Solenoid Main Valve Assembly) (Open) *4 Canister
            *5 Purge VSV (Closed) *6 Leak Detection Pump (Off)
            *7 Canister Pressure Sensor *8 Vent Valve (Vent Closed)
            *9 Canister Pump Module - -
            *a Atmosphere - -

          5. The timing of the fuel vapor-containment valve (fuel tank solenoid main valve assembly) stuck close check is as follows:

            A01R26EE05