P0455
DTC P0455 EVAP. EMISSION SYSTEM-LEAK DETECTED (LARGE LEAK)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
The ECM closes the Canister Close Valve (CCV) at the charcoal canister to seal off the evaporative emission system and then opens purge control valve (PCSV) to generate a vacuum in the fuel tank. This vacuum generation phase will determine if there is a large leak like tank cap open or canister shut off valve (CCV) stuck open. The ECM sets DTC P0455 if the pressure in the fuel tank does not drop as low as predetermined threshold during predetermined maximum vacuum generation period. If the same error code is set in the next driving cycle, the ECM illuminates the MIL.
DTC Detecting Condition:
MONITOR DTC STATUS
NOTE: If any codes relating to Fuel tank pressure sensor, Canister closing valve or PCSV circuits are present, do ALL REPAIRS associated with those codes before proceeding with this troubleshooting tree.
1. Start engine to normal operating temperature.
NOTE: Evaporative Emissions Systems (EVAP) Leak Tests can be run by the Scan Tool. The tests are automated and provide either a pass-fail result or directions to check for DTCs.
2. Install scan tool and clear DTC.
3. Perform "EVAP. LEAKAGE TEST" mode referring to enable conditions as below.
NOTE: EVAP Leakage Test enable conditions.
- Following conditions must be fulfilled to start the test.
1. Engine warm up at Idle Status
2. No relevant DTC
3. Fuel level is below 80%
4. Is DTC P0455 set again?
YES - Go to next step as below
NO - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
FUEL FILLER CAP & PIPE INSPECTION
1. Check fuel filler cap for being tightly installed, has O-ring seal installed and is in good condition.
2. Verify cap releases pressure I vacuum at specified values.
Specification : Approx. 2 psi pressure and approximately 1.5 inches of mercury vacuum).
3. Are cap, O-ring and release pressures okay?
YES - Thoroughly check fuel filler pipe for cracks, damage and O-ring seat for deformation and replace as necessary. Go to "PCSV to Intake manifold Line Inspection" procedure
NO - Replace fuel filler cap and go to "Verification of Vehicle Repair" procedure
PCSV TO INTAKE MANIFOLD LINE INSPECTION
1. Ignition "OFF".
2. Disconnect the hose leading from the PCSV to intake manifold at intake manifold.
3. Using a vacuum pump, apply vacuum to the manifold side of the vacuum hose and verify PCSV holds vacuum.
4. Ignition "ON" & Engine "OFF".
5. Install scantool and select "EVAP PURGE VALVE" on the Actuation Test mode.
6. Activates "EVAP PURGE VALVE" by pressing "STRT (F1)" key.
7. Verify PCSV release vacuum while valve is activating (should hear a faint click from PCSV).
Specification:
8. Repeat this procedure 4 or 5 times to ensure PCSV reliability.
9. Is PCSV working properly?
YES - Go to next step as below
NO - Verify arrow on PCSV is pointing towards intake manifold. If it is not, reverse installation. Reinstall as necessary and go to "Verification of Vehicle Repair" procedure.
- If OK, thoroughly check fuel vapor hoses and hose clamps between PCSV and intake manifold. Repair as necessary. If OK, test with a new PCSV and check for proper operation. If problem is corrected, replace PCSV and go to "Verification of Vehicle Repair" procedure
CANISTER CLOSING VALVE (CCV) LINE INSPECTION
1. Reconnect all EVAP hardware that was previously disconnected.
2. Disconnect hose connecting Canister Closing Valve (CCV) to canister.
3. Ignition "ON" & Engine "OFF".
4. Blow air to the canister side of the valve and verify air escapes to the air filter side.
5. Install scantool and select "CANISTER CLOSE VALVE" on the Actuation Test mode.
6. Activates "CANISTER CLOSE VALVE" by pressing "STRT (F1)" key.
7. Blow air into hose and verify air does not escape.
8. Repeat this procedure 4 or 5 times to ensure CCV reliability.
9. Is CCV working properly?
YES - Go to next step as below
NO - Check for cracks or damage in hose connecting CCV and canister. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure. If OK, replace CCV. If CCV was stuck closed, inspect all lines and canister for liquid fuel. Replace any contaminated components and blow out lines and go to "Verification of Vehicle Repair" procedure
FUEL TANK PRESSURE SENSOR (FTPS) INSPECTION
1. Ignition "ON" & Engine "OFF".
2. Disconnect the hose connecting FTPS and fuel pump at FTPS side. (Do not disconnect FTPS harness connector).
3. Install vacuum pump to the FTPS nipple.
4. Apply vacuum pressure 0.4 inHg(1.5 kPa) to 1.0 inHg(3.4 kPa) and measure FTPS output voltage between terminal 2 (back probe) of the FTPS harness connector and chassis ground.
Specification : Voltage increases proportionally with decreasing pressure (Approx. 2.5 V to 4.5 V)
CAUTION: Do not apply vacuum pressure less than 1.1 inHg(3.8 kPa)
5. Is voltage within the specification?
YES - Go to "Purge Control Solenoid Valve (PCSV) Inspection" procedure
NO - Check for cracks or damage in hose connecting canister and fuel pump. Repair or replace as necessary. Check for open or short in FTPS harness. Repair as necessary. If OK, test with a new FTPS and check for proper operation. If problem is corrected, replace FTPS and go to "Verification of Vehicle Repair" procedure
PCSV TO CANISTER LINE INSPECTION
1. Check for leakage in hose
1. Reconnect all EVAP hardware that was previously disconnected.
2. Disconnect the hose leading from the canister to the PCSV at canister.
3. Using a vacuum pump, apply specified vacuum [Approx. 4 inHg (14 kPa)] to the manifold side of the valve for minute and verify PCSV holds vacuum.
4. Is pressure within specification?
YES - Go to next step as below
NO - Check for cracks or damage in hose connecting PCSV and canister. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
2. Check for leakage in canister.
1. Disconnect hose clamps and remove canister assembly.
2. Block the hose of between:
- Canister and fuel filler neck
- Canister and CCV
- Canister and PCSV
3. Apply maximum of 4 inHg(14 kPa) pressure through fuel tank port from canister.
4. With system sealed and pressurized, check for leaks.
5. Were any leak(s) found?
YES - Repair or replace leaking system component(s) and go to "Verification of Vehicle Repair" procedure
NO - Go to "Fuel Tank Line Inspection" procedure
FUEL TANK LINE INSPECTION
1. Relieve the fuel system pressure and remove the fuel tank
CAUTION: Before removing the fuel tank, make sure the fuel hoses are not leaking.
2. Block all of the following outlets:
1. Fuel lines
2. Fuel filler neck
3. Apply maximum of 10 cmHg(4 inHg) pressure to the EVAP. hose at the fuel tank. Then, pinch the EVAP. hose to retain the pressure.
4. Check the suspect area for leaks with a soap solution.
5. Were any leak(s) found?
YES - Repair or replace leaking system component(s) and go to "Verification of Vehicle Repair" procedure
NO - Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure
VERIFICATION OF VEHICLE REPAIR
1. Reconnect all EVAP hardware that was previously disconnected.
2. Start engine to normal operating temperature.
NOTE: Evaporative Emissions Systems (EVAP) Leak Tests can be run by the Scan Tool. The tests are automated and provide either a pass-fail result or directions to check for DTCs.
3. Install scan tool and clear DTC.
4. Perform "EVAP. LEAKAGE TEST" mode referring to enable conditions as below.
NOTE: EVAP Leakage Test enable conditions
- Following conditions must be fulfilled to start the test.
1. Engine warm up at Idle Status
2. No relevant DTC
3. Fuel level is below 80%
5. Monitoring for (pending) DTC. is the same DTC set?
YES - Go to the applicable troubleshooting procedure.
NO - System performing to specification at this time.