P0455

GENERAL DESCRIPTION

Due to the increasing ambient temperature of the fuel and the return of unused hot fuel from the engine, fuel vapors are generated in the tank. In order to control the release of these vapors to the atmosphere, the evaporative emissions control system is used. The evaporative emission control system reduces hydrocarbon (HC) emissions by trapping fuel tank vapors until they can be burned in the combustion process. Evaporating fuel is stored in a charcoal canister until it can be flushed into the intake manifold. The evaporative emission control system is made up of a fuel tank that can be completely sealed from outside air, a Fuel Tank Pressure Sensor (FTPS), a Canister Close Valve (CCV) that seals the canister from the outside air, a canister filled with activated charcoal granules, a Purge Control Solenoid Valve (PCSV). The evaporative emission system can be checked for leaks by sealing the system off from the outside air, creating a vacuum, and monitoring if the system can hold that vacuum sufficiently for a set amount of time. If it cannot, a leak exists somewhere in the system.

DTC DESCRIPTION

Checking output signals from fuel tank pressure sensor under evap.system test, if fuel tank's vacuum is lower than prescribed threshold, PCM sets P0455 and then MIL(Malfunction Indication Lamp) turns on.

DTC DETECTING CONDITION





MONITOR DTC STATUS

1. Check DTC Status
(1) Connect scantool to Data Link Connector(DLC).
(2) IG "ON".
(3) Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.




(5) Is parameter displayed "Present fault"?
YES
> Check the Fuel Filler Cap is installed. If not, after closing it, go to "Evap.Leakage Test" as below with scan tool.
NO
> Go to "Evap.Leakage Test" as below with scan tool.
2. Evap. Leakage Test
(1) Cool the vehicle down for about two hours to prevent misdiagnosis.
(2) Install scan tool and IG "ON" and then clear DTC.
(3) Select and press "EVAP.LEAKAGE TEST" mode in the scan tool.
(4) Check if the vehicle is under test conditions as below [Fig 1].
(5) If OK, Start engine and restart Evap.Leakage Test again[Fig 2].




(6) Is the same DTC set after the Evap.leakage test with scan tool ?
YES
> Go to "System Inspection" procedure.
NO
> Repeat "Evap.leakage test" with scan tool after cool the vehicle down sufficiently. If the same DTC isn't displayed after the test, it was intermittent fault. Go to "Verification of vehicle Repair" procedure.

SYSTEM INSPECTION

1. Check Fuel Filler Cap
(1) Check the Fuel Filler Cap is installed and properly tightened.
(2) Check if the Fuel Filler Cap seal is missing or damaged.
(3) Is the Fuel Filler Cap OK?
YES
> Go to "Check vapor hoses for leakage in fuel system" as below
NO
> Replace the Fuel Filler Cap and go to "Verification of Vehicle Repair" procedure.
2. Check vapor hoses for leakage in fuel system
(1) Check vapor hoses between the following components for leakage:
A. Intake manifoled ~ Purge control solenoid valve (PCSV)
B. Purge control solenoid valve (PCSV) ~ Canister
C. Canister ~ Canister close valve (CCV)
D. Canister ~ fuel tank
(2) Does a leak exist?
YES
> Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
NO
> Go to "Check fuel filler pipe for crack or leakage" as below
3. Check fuel filler pipe for crack or leakage
(1) Check that there is crack or leakage in fuel filler pipe
(2) Is there any crack or leakage ?
YES
> Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
NO
> Go to "Component inspection" procedure.

COMPONENT INSPECTION

1. Check CCV for leakage
(1) Disconnect the hose leading from the CCV to Canister at CCV.
(2) Visually Check any tear of the hose leading from the CCV to Canister
(3) When the CCV operates, apply a vacuum at the nipple and verify that the CCV holds vacuum.
(4) Does a leak exist?
YES
> Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
> Go to "Check Canister for leakage" as below
2. Check Canister for leakage
(1) Disconnect the hose leading from the CCV to Canister at Canister.
(2) When the other nipples are plugged, apply a vacuum at the vent nipple and verify that the Canister holds vacuum.
(3) Does a leak exist?
YES
> Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
> Go to "Check fuel tank for leakage" as below
3. Check fuel tank for leakage
(1) Check fuel tank for crack or leakage.
(2) Does a leak exist?
YES
> Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
> Carefully perform this troubleshooting procedures all over again from the beginning.

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
2. Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
3. Read "DTC Status" parameter.
4. Is parameter displayed "History(Not Present) fault"?
YES
> System performing to specification at this time. Clear the DTC
NO
> Go to the applicable troubleshooting procedure.