SFI SYSTEM, Diagnostic DTC:P0455, P0456

DTC Code DTC Name
P0455 Evaporative Emission Control System Leak Detected (Gross Leak)
P0456 Evaporative Emission Control System Leak Detected (Very Small Leak)

DTC SUMMARY

DTC No. Monitoring Item Malfunction Detection Condition Trouble Area Detection Timing Detection Logic
P0455 EVAP gross leak

Leak detection pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure is measured. Reference pressure is measured at start and end of leak check.

If stabilized pressure is higher than [second reference pressure x 0.2], ECM determines that EVAP system has a large leak.

  • Fuel cap (loose)

  • Leakage from EVAP line (canister - fuel tank)

  • Leakage from EVAP line (purge VSV - canister)

  • Leakage from canister pump module

  • Leakage from fuel tank

  • Leakage from canister

 While engine switch off 2 trip
P0456 EVAP small leak

Leak detection pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure is measured. Reference pressure measured at start and end of leak check.

If stabilized pressure is higher than second reference pressure, ECM determines that EVAP system has a small leak.

 While engine switch off 2 trip

DESCRIPTION

The description can be found in EVAP (Evaporative Emission) System Click here.

MONITOR DESCRIPTION

5 hours* after the engine switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

Tech Tips

*: If the engine coolant temperature is not less than 35°C (95°F) 5 hours after the engine switch is turned off, the monitor check starts 2 hours later. If it is still not less than 35°C (95°F) 7 hours after the engine switch is turned off, the monitor check starts 2.5 hours later.

Sequence Operation Description Duration
- ECM activation Activated by soak timer 5, 7 or 9.5 hours after engine switch turned off. -
A Atmospheric pressure measurement

Vent valve is turned off (vent) and EVAP system pressure is measured by ECM in order to register atmospheric pressure.

If pressure in EVAP system is not between 70 kPa(abs) and 110 kPa(abs) [525 mmHg(abs) and 825 mmHg(abs)], ECM cancels EVAP system monitor.

 60 seconds
B First reference pressure measurement In order to determine reference pressure, leak detection pump creates negative pressure (vacuum) through reference orifice and then ECM checks if leak detection pump and vent valve operate normally. 360 seconds
C EVAP system pressure measurement

Vent valve is turned on (closed) to shut EVAP system.

Negative pressure (vacuum) is created in EVAP system, and EVAP system pressure is then measured.

Write down measured value as it will be used in leak check. If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor.

 15 minutes*
D Purge VSV monitor

Purge VSV is opened and then EVAP system pressure is measured by ECM.

Large increase indicates normal.

 10 seconds
E Second reference pressure measurement

After second reference pressure measurement, leak check is performed by comparing first and second reference pressure measurements.

If stabilized system pressure is higher than second reference pressure, ECM determines that EVAP system is leaking.

 60 seconds
- Final check Atmospheric pressure is measured and then monitoring result is recorded by ECM. -

*: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

A01HNKTE37
Text in Illustration
*1 Purge VSV: Off (Closed) *2 Purge VSV: On (Open)
*3 Vent Valve: Off (Vent) *4 Vent Valve: On (Closed)
*5 Leak Detection Pump: Off *6 Leak Detection Pump: On
*7 Reference Orifice (0.02 inch) *8 Canister Pressure Sensor
*9 Canister *10 Fuel Tank
*11 Canister Pump Module *12 Canister Filter
*a

Operation A:

Atmospheric Pressure Measurement

 *b

Operation B, E:

Reference Pressure Measurement
*c

Operation C:

EVAP System Pressure Measurement

 *d

Operation D:

Purge VSV Monitor
*e Atmospheric Pressure *f Negative Pressure

MONITOR STRATEGY

Required Sensors/Components (Main)

Purge VSV

Canister pump module
Required Sensors/Components (Related) -
Frequency of Operation Once per driving cycle
Duration Within 20 minutes (varies with amount of fuel in tank)
MIL Operation 2 driving cycles
Sequence of Operation None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored None
Atmospheric pressure 70 kPa(abs) [525 mmHg(abs)] or higher, and less than 110 kPa(abs) [825 mmHg(abs)]
Battery voltage 10.5 V or higher
Vehicle speed Less than 4 km/h (2.5 mph)
Engine switch Off
Time after key-off 5, 7 or 9.5 hours
Canister pressure sensor malfunction (P0452, P0453) Not detected
Purge VSV Not operated by scan tool
Vent valve Not operated by scan tool
Leak detection pump Not operated by scan tool
Both of the following conditions met before-key off Conditions 1 and 2
1. Duration that vehicle is driven 5 minutes or more
2. EVAP purge operation Performed
Engine coolant temperature 4.4°C (40°F) or higher, and less than 35°C (95°F)
Intake air temperature 4.4°C (40°F) or higher, and less than 35°C (95°F)

TYPICAL MALFUNCTION THRESHOLDS

P0455: EVAP Gross Leak
EVAP pressure when vacuum introduction is complete Higher than [reference pressure x 0.2]
P0456: EVAP Small Leak
EVAP pressure when vacuum introduction is complete Between reference pressure and [reference pressure x 0.2]

MONITOR RESULT

Refer to EVAP System Click here.

CONFIRMATION DRIVING PATTERN

Note


  • The Evaporative System Check (Automatic Mode) consists of 6 steps performed automatically by the Techstream. It takes a maximum of approximately 24 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 higher, a large amount of vapor forms and any check results become inaccurate. When performing the Evaporative System Check, keep the fuel temperature less than 35°C (95°F).


  1. Connect the Techstream to the DLC3.

  2. Turn the engine switch on (IG) and turn the Techstream on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the Techstream on.

  6. Enter the following menus: Powertrain / Engine / Utility / Evaporative System Check / Automatic Mode.

  7. After the Evaporative System Check is completed, check for All Readiness by entering the following menus: Powertrain / Engine / Utility / All Readiness.

  8. Input the DTC: P0455 or P0456.

  9. Check the DTC judgment result.

    Techstream Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

  10. If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs Click here.

    Tech Tips


    • If a permanent DTC is output, the system is malfunctioning.

    • If no permanent DTC is output, the system is normal.

INSPECTION PROCEDURE

Refer to EVAP System Click here.