P0448
COMPONENT 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
Checking output signals from CCV every 10 sec. under detecting condition, if signals indicating short to battery in the circuit are detected for more than 5 sec., ECM sets P0448. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC DETECTING CONDITION
SPECIFICATION
SCHEMATIC DIAGRAM
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 F5(INFO) to check DTC's information from the DTCs menu
(4) Read "DTC Status" parameter.
(5) Is "Present" Fault displayed?
YES
> Go to "Terminal and Connector inspection" procedure.
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, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
> Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
> Go to " Control Circuit Inspection " procedure
CONTROL CIRCUIT INSPECTION
1. Check for short to battery in harness
(1) Ignition "OFF"
(2) Disconnect CCV connector
(3) Measure resistance between terminal "2" and "1" of CCV harness connector.
Specification : Infinite
(4) Is the measured resistance within specifications?
YES
> Go to " Component Inspection " procedure.
NO
> Check short to battery in harness.
> Repair or replace as necessary and then, go to " Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1. Check CCV
(1) Ignition "OFF"
(2) Measure resistance between terminals "1" and "2" of the CCV connector.
Specification: Approx. 15.5 - 18.5 Ohms (20°C(68°F)
(3) Monitor the CCV signal waveform and verify that the ground voltage is less than approx. 0.3V (1) and the surge voltage (2) is between 40 V and 60 V.
(4) Is the CCV normal?
YES
> Substitute with a known - good ECM and check for proper operation.
> If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure,
NO
> Substitute with a known - good CCV and check for proper operation.
> If the problem is corrected, replace CCV and go to "Verification of Vehicle Repair" procedure.
NOTE:
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by ECM. After testing ECM on the vehicle, use this function before reusing the ECM
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 F5(INFO) 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 "History (Not Present)" fault displayed?
YES
> System performing to specification at this time. Clear the DTC
NO
> Go to the applicable troubleshooting procedure.