SFI SYSTEM(w/ Canister Pump Module), Diagnostic DTC:P0455 and P0456

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0455	Evaporative Emission Control System Leak Detected (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 tank 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	Comes on	DTC stored
P0456	Evaporative Emission Control System Leak Detected (Very 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.	Fuel tank 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	Comes on	DTC stored

DTC No.	Monitoring Item	Detection Timing	Detection Logic
P0455	EVAP gross leak	While ignition switch off	2 trip
P0456	EVAP small leak	While ignition switch off	2 trip

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

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5 hours*1 after the ignition 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.

Sequence	Operation	Description	Duration
-	ECM activation	Activated by soak timer 5, 7 or 9.5 hours after ignition 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.

*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

• (a) P0455: EVAP (Evaporative Emission) gross leak

  In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than [second reference pressure x 0.2] (near atmospheric pressure), the ECM determines that the EVAP system has a large leak, illuminates the MIL and stores the DTC (2 trip detection logic).

• (b) P0456: EVAP very small leak

  In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than second reference pressure, the ECM determines that the EVAP system has a small leak, illuminates the MIL and stores the DTC (2 trip detection logic).

  

Required Sensors/Components	Purge VSV Canister pump module
Frequency of Operation	Once per driving cycle

1. Connect the GTS to the DLC3.

2. Turn the ignition switch to ON and turn the GTS on.

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

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

5. Turn the ignition switch to ON and turn the GTS on.

6. Enter the following menus: Powertrain / Engine and ECT / 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 and ECT / Utility / All Readiness.

8. Input the DTC: P0455 or P0456.

9. Check the DTC judgment result.

   GTS 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

   Tip:

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

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