P0442
P0442 EVAP. EMISSION SYSTEM-LEAK DETECTED (SMALL LEAK)GENERAL DESCRIPTION
The evaporative emission control 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 ECM controls the Purge Control Solenoid Valve (PCSV) to purge any collected vapors from the canister back to the engine for combustion. This valve is actuated by the purge control signal from the ECM and controls fuel vapor from the canister to the intake manifold.
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:
MONITOR DTC STATUS
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-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
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 P0441 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.
PCSV 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)
8. Repeat this procedure 4 or 5 times to ensure PCSV reliability.
Specification:
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 CLOSE 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 blowout lines and go to "Verification of Vehicle Repair" procedure.
FUEL TANK PRESSURE SENSOR INSPECTION
1. Ignition "ON" & Engine "OFF" .
2. Measure FTPS output voltage between terminal 3 (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)
Specification:
3. Is voltage within the specification?
YES - Go to next step as below.
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 1 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 next step as below.
FUEL TANK LINE INSPECTION
1. Relieve the fuel system pressure and remove the fuel tank
WARNING: 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. Return vehicle to original condition
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.