P0442
DTC P0442 EVAP. EMISSION SYSTEM-LEAK DETECTED (SMALL LEAK)GENERAL DESCRIPTION
The Small Leak test determines the presence of a leak in the evaporative system that is 0.040" diameter (1.0 mm) or larger, as defined by CARB. The EVAP(Evaporative System Diagnostics) will only perform this test when idle conditions are present and the Large Leak test has reported a "pass" condition, indicating that the current tank vacuum level is approximately 10.2inH2O.
DTC DESCRIPTION
This test detects a leak across the purge valve by measuring an increase in evaporative system vacuum. A leak across the purge valve can allow hydrocarbons from the tank to leak to the atmosphere when the engine is off. The test should be calibrated to detect a 0.02 inches (0.5mm) leak path across the purge valve. This test does not require idle conditions to run. Checking output signal from tank vacuum under detecting condition, if the signal is high than threshold, PCM sets P0442. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till 1 driving cycle.
DTC Detecting Condition:
MONITOR SCANTOOL DATA
1. Warm-up 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-fall 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.
4. Monitoring for (pending) DTC by performing" DIAGNOSTIC TROUBLE CODES"or "MONITORING TEST RESULTS".
5. Is the same DTC set?
YES: Go to "System Inspection" procedure.
NO: Fault is intermittent caused by poor contact in sensor's and/or PCM's connector or was repaired and PCM 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,
SYSTEM INSPECTION
1. Check vapor hoses for leakage in fuel system.
1. Check vapor hoses between the following components for leakage:
- Intake manifold Purge control solenoid valve (PCSV)
- Purge control solenoid valve (PCSV) Canister
- Canister Canister close valve (CCV)
- 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 leakage" as below.
2. Check fuel filler pipe for crack or leakage.
1. Check that there is crack or leakage in fuel filler pipe.
2. Does a malfunction exist?
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. When the CCV is operated, apply a vacuum at the nipple and verify that the CCV 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 Canister for leakage" as necessary.
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: Substitute with a known - good PCM and check for proper operation.
If the problem is corrected, replace PCM 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 monetized by PCM. After testing PCM on the vehicle, use this function to reuse the PCM on the others
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has beer corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all readiness tests have been verified as" Complete"
5. Are any DTCs present?
YES: Go to the applicable trouble shooting procedure.
NO: System is performing to specification at this time.