P0449
DTC P0449 EVAP. EMISSION SYSTEM-VENT VALVE/SOLENOID CIRCUITComponent Location:
GENERAL DESCRIPTION
The evaporative emissions system prevents hydrocarbon (HC) vapors from the fuel tank from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The Canister Closing Valve (CCV) closes off the air inlet into the canister for leak detection of the evaporative emission system. The CCV also prevents fuel vapors from escaping from the canister. When the engine purges the HC vapors from the canister, the clean air comes into the canister through the canister air-filter and the CCV.
DTC DESCRIPTION
The ECM measures pressure in the fuel tank by means of tank pressure sensor during all engine operating states except engine stop and start. The DTC P0449 is set if pressure is lower than predetermined threshold.
If same error code is set in the next driving cycle, the ECM illuminates the MIL.
DTC Detecting Condition:
Specification:
Schematic Diagram:
MONITOR DTC STATUS
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
2. Press F4(DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Read "DTC Status" parameter.
5. Is parameter displayed "History(Not Present) fault"?
NOTE:
- History (Not Present) fault: DTC occurred but has been cleared.
- Present fault ft: DTC is occurring at present time.
YES: 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.
NO: Go to "Component Inspection" procedure.
COMPONENT INSPECTION
1. Ignition "OFF".
2. Disconnect CCV connector.
3. Measure resistance between terminals 1 and 2 of the CCV connector(Component side).
Specification: Approx. 23.9-26.9Ohm at 20 degrees C (68 degrees F)
4. Is resistance within the specification?
YES: Go to next step as below.
NO: Check CCV for contamination, deterioration, or damage. Substitute with a known-good CCV and check for proper operation. If the problem is corrected, replace CCV and then go to "Verification of Vehicle Repair" procedure.
CANISTER AIR-FILTER INSPECTION
1. Disassemble the Canister Air-Filter and hose from their respective positions.
2. Check the Canister air-filter for contamination.Disconnect CCV connector.
3. Is Canister Air-Filter contaminated with dust?
YES: Replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO: Go to "Canister Closing Valve(CCV) inspection" procedure.
CANISTER CLOSING VALVE (CCV) LINE INSPECTION
1. Return vehicle to original condition.
2. Ignition "OFF".
3. Disconnect the hose connecting Canister Closing Valve(CCV) to canister.
4. Blow air to the canister side of the valve and verify air escapes to the air filter side.
5. Turn ignition on and jumper a wire to GND(back probe) at terminal 2 of the ECM connector(CCV valve should click).
6. Blow air into hose and verify air does not escape.
7. Repeat this procedure 4 or 5 times to ensure CCV reliability.
8. Is CCV working properly?
NOTE: If hose was pinched or restricted:
1. Fueling would be difficult if not impossible.
2. Restriction or blockage could cause pressure to accumulate in tank triggering a P0451.
YES: 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.
NO: Replace CCV. If CCV was stuck closed, inspect all lines and canister for liquid fuel. Replace any contaminated components and blow out lines.
Go to "Verification of Vehicle Repair" procedure.
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.