P0442
DTC P0442 EVAP EMISSION CONTROL SYSTEM SMALL LEAK (1 MM)
Component Location:
GENERAL DESCRIPTION
The DM-TL (Diagnostic Module Tank Leakage) is used to monitor the evaporative system for leaks. The diagnostic module consists of an air filter, an electrical driven air pump, a change-over valve and a 0.02 inch orifice for reference measurement. Heated type Module applied to improved Leakage Detection Module. Using the heated DM-TL can completely eliminate the humidity influence. So, the Leakage detection is never stopped caused by the current fluctuation (due to dew effects at extreme high humidity).
DTC DESCRIPTION
The PCM 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. After vacuum generation, the PCM measures pressure differential curve in the fuel tank and sets DTC P0442 or P0456 if the vacuum generated within a monitoring period increases above a defined threshold. If same error code is set in the next driving cycle, the PCM illuminates the MIL.
DTC Detecting Condition:
Schematic Diagram:
MONITOR DTC STATUS
This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
3. Evap. Leakage Test
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.
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
3. Perform "07 EVAP. LEAKAGE TEST" mode
4. Is DTC P0442 set again?
YES: Go to "W/Harness Inspection" procedure.
NO: Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection,beading, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification vehicle Repair" procedure.
TERMINAL & CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. 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 "Component Inspection" procedure.
COMPONENT INSPECTION
1. Check Fuel Filler Cap
1. Warm-up engine to normal operating temperature.
2. Check fuel filler cap, O-ring seal for being tightly installed, and in good condition.
3. Verify cap releases vacuum at specified values (approximately 2psi pressure and approximately 1.5 inches Hg vacuum)
4. Are cap, O-ring and release pressures OK?
YES: Go to "Check Fuel Filler Pipe" as below
NO: Substitute with a known-good Fuel Filler Cap and check for proper operation. If the problem is corrected, replace Fuel Filler Cap and then go to "Verification of Vehicle Repair" procedure.
2. Check Fuel Filler Pipe
1. Check fuel filler pipe for cracks, damage and c-ring seat for deformation.
2. Is fuel filler pipe okay?
YES: Go to "Thoroughly check all Fuel vapor hoses clamps " as below
NO: Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
3. Thoroughly check all Fuel vapor hoses clamps between;
- Canister and rollover valve.
- Canister and ORVR valves.
- Canister and catcher tank.
- Canister and DMTL.
- Canister and PSV.
- PSV and intake manifold(At this point, verify arrow on PSV is pointing towards intake manifold. If it is not, reverse installation).
1. With system sealed and pressurized, check for leaks with a R134a leak detector.
2. Are vapor hoses and clamps okay?
YES: Go to "Check PSV" as below
NO: Replace all cracked/damaged hoses loose clamps go to "Verification Vehicle Repair" procedure.
4. Check PSV
1. Turn ignition OFF and disconnect hose leading from PSV to intake manifold at PSV. Draw a vacuum at nipple and verify PSV hold vacuum. Turn ignition to ON and jumper a wire to chassis ground at PSV control terminal 1 (should hear a faint click from PSV). Vacuum could bleed off. Repeat this procedure 4 or 5 times to ensure PSV reliability.
2. Is PSV working properly?
YES: Go to "Check DM-TL" as below
NO: Substitute with a known-good PCV and check for proper operation. If the problem is corrected, replace PCV and then go to "Verification of Vehicle Repair" procedure.
5. Check DM-TL
1. Temporarily install a new DM-TL and check for proper operation.
2. Is problem still remained?
YES: Substitute with a known-good DM-TL and check for proper operation. If the problem is corrected, replace DM-TL 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 then 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. 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 rediness test have been verified as "Complete".
5. Are any DTCs present?
YES: Go to the applicable troubleshooting procedure.
NO: System is performing to specification at this time.