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DTC P0442: Evaporative
Emission System Leak Detected (Small Leak)
TECHNICAL DESCRIPTION
- The ECM monitors the Evaporative Emission (EVAP) System
pressure.
- The ECM controls the evaporative emission ventilation solenoid. It closes the evaporative emission
ventilation solenoid to seal the evaporative emission canister side of the system.
- The evaporative emission purge solenoid is opened to allow manifold vacuum to create
low pressure (vacuum) in the EVAP system.
- When the EVAP system develops a vacuum of 2 kPa (0.29 psi), the evaporative emission
purge solenoid is closed and the fuel system vacuum is maintained at 2 kPa (0.29 psi).
- The ECM determines whether there is a leak in the EVAP system by monitoring the
vacuum inside the fuel tank.
- The test is stopped when fuel vapor pressure exceeds predetermined limits.
DESCRIPTIONS OF MONITOR METHODS
- Measure reverting pressure after depressurizing by intake manifold negative
pressure and detect malfunction if reverting pressure rises largely.
MONITOR EXECUTION
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored
below)
- Evaporative emission purge solenoid monitor
- Evaporative emission purge system monitor
- Fuel tank differential pressure sensor monitor
- Evaporative emission ventilation solenoid monitor
- Fuel level sensor monitor
- Fuel temperature sensor monitor
Sensor (The sensors below are determined to be normal)
- Mass airflow sensor
- Barometric pressure sensor
- Intake air temperature sensor
- Engine coolant temperature sensor
DTC SET CONDITIONS
Logic Flow Chart (Monitor Sequence)
Check Conditions
- Amount of remaining fuel is 15 - 40 percent of capacity.
- Engine coolant temperature is 36°C (97°F) or less when the engine
is started.
- Intake air temperature is 36°C (97°F) or less when the engine
is started.
- Engine coolant temperature is higher than 60°C (140°F).
- Intake air temperature is higher than -10°C (14°F)
- Fuel tank temperature is less than 36°C (97°F)
- Power steering pressure switch: "OFF"
- When the evaporative emission purge solenoid and evaporative emission ventilation
solenoid are closed, the pressure in the fuel tank is less than 451 Pa (0.13 in.Hg).
- The pressure fluctuation is less than 647 Pa (0.19 in.Hg).
- Barometric pressure is higher than 76 kPa (22.4 in.Hg).
- Vehicle speed is 20 km/h (1.2 mph) or more.
- Fuel tank differential pressure sensor output voltage is 1.0 - 4.0 volts.
- At least 10 seconds have passed since the last monitor was complete.
Judgement Criterion
- Internal pressure of the fuel tank has changed more than 1,010 Pa (0.147 psi) in
20 seconds after the tank and vapor lines were closed.
| note |
The monitoring time (75 - 125 seconds) depends on the fuel level and the temperature
in the fuel tank. The next monitoring occurs at least 10 seconds later.
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Check Conditions
- Amount of remaining fuel is 40 - 85 percent of capacity.
- Engine coolant temperature is 36°C (97°F) or less when the engine
is started.
- Intake air temperature is 36°C (97°F) or less when the engine
is started.
- Engine coolant temperature is higher than 20°C (68°F).
- Intake air temperature is higher than -10°C (14°F)
- Fuel tank temperature is higher than 36°C (97°F).
- When the evaporative emission purge solenoid and evaporative emission ventilation
solenoid are closed, the pressure in the fuel tank is less than 324 Pa (0.09 in.Hg).
- Barometric pressure is higher than 76 kPa (22.4 in.Hg).
- Fuel tank differential pressure sensor output voltage is 1.0 - 4.0 volts.
- At least 10 seconds have passed since the last monitor was complete.
Judgment Criterion
- Internal pressure of the fuel tank has changed more than 1,922 Pa (0.279 psi) in
88 seconds after the tank and vapor lines were closed.
| note |
The monitoring time (10 - 14 minutes) depends on the fuel level and the temperature
in the fuel tank. The next monitoring occurs at least 10 seconds later.
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OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 5 
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TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
- Loose fuel cap.
- Fuel cap relief pressure is incorrect.
- Evaporative emission canister seal is leaking.
- Fuel tank, purge line or vapor line seal is leaking.
- Evaporative emission ventilation solenoid does not seal.
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Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
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STEP 1. Using scan tool MB991958, check the evaporative emission
system monitor test.
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| caution |
- To prevent damage to scan tool MB991958, always turn the ignition switch
to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
- During this test, the ECM will automatically increase the engine speed to 1,600
r/min or greater. Check that the transaxle is set to "P" position.
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(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Erase the DTCs using scan tool MB991958.
(4)Check that the fuel cap is securely closed (Tighten until three clicks are heard).
(5)Start the engine.
(6)Select "System Test."
(7)Select "Evap Leak Mon."
(8)During this test, keep the accelerator pedal at the idle position.
(9)Keep the engine speed and engine load within the specified range. When the monitor
test starts, the "In Progress" item on scan tool MB991958 will change from "NO" to "YES".
(10) Turn the ignition switch to the "LOCK" (OFF) position, and disconnect scan tool
MB991958.
Q.
Is "Evap Leak Mon. Completed. Test Failed and DTCs Set" displayed on scan tool MB991958?
 A malfunction has been detected during the monitor test. Refer to the Diagnostic
Trouble Code Chart and diagnose any other DTCs that are set .
If no other DTC’s have been set, go to Step 2 .
NO <"Evap Leak Mon. Completed. Test Passed" is displayed on scan tool MB991958.> : The evaporative emission system is working properly at this time. Explain to the
customer that an improperly tightened fuel cap can cause the MIL to illuminate. Return the vehicle
to the customer.
NO <"Evap Leak Mon. Discontinued. Retest again from the first" is displayed on scan
tool MB991958.> : The EVAP monitor has been interrupted during the test. Turn the ignition switch
to the "LOCK" (OFF) position once, and repeat the monitoring from Step 1 .
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STEP 2. Check the evaporative emission purge solenoid for leaks.
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(1)Disconnect hose A from the evaporative emission purge solenoid.
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(2)Connect the hose of the hand pump (pressure-application type) to the chamber side nipple
of the evaporative emission purge solenoid.
(3)Use the hand pump (pressure-application type) to confirm that the evaporative emission
purge solenoid holds vacuum.
(4)Connect hose A to the evaporative emission purge solenoid.
Q.
Does the evaporative emission purge solenoid hold pressure?
Go to Step 3 .
 Replace the evaporative emission purge solenoid. Then go to Step 13 .
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STEP 3. Check for leaks in evaporative emission hose
A, chamber and hose B.
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(1)Use a hand vacuum pump to check hose A, chamber and hose B.
Q.
Do the hoses and chamber hold vacuum?
Go to Step 4 .
Replace any damaged hose or chamber. Then go to Step 13 .
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STEP 4. Check for leaks in evaporative emission hose
C.
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(1)Use a hand vacuum pump to check hose C.
Q.
Does hose C hold vacuum?
Go to Step 5 .
Replace any damaged hose. Then go to Step 13 .
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STEP 5. Using scan tool MB991958, check actuator test item 15: Evaporative
emission ventilation solenoid.
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(1)Remove the canister cover.
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(2)Remove the evaporative emission ventilation solenoid. Do not disconnect the connector.
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(3)Connect the hose of the hand vacuum pump to the canister side nipple of the evaporative
emission ventilation solenoid.
(4)Turn the ignition switch to the "ON" position.
(5)Set scan tool MB991958 to actuator testing mode for item 15: Evaporative Emission
Ventilation Solenoid.
- While the evaporative emission ventilation solenoid is energized,
operate the hand vacuum pump and confirm that the solenoid holds vacuum.
(6)Turn the ignition switch to the "LOCK" (OFF) position.
(7)Disconnect the hand vacuum pump, and reinstall the evaporative emission ventilation
solenoid.
(8)Reinstall the canister cover.
Q.
Did the evaporative emission ventilation solenoid hold vacuum?
Go to Step 6 .
Replace the evaporative emission ventilation solenoid Then go to Step 13 .
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STEP 6. Perform the pressure test on the evaporative emission system.
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(1)Disconnect hose D from the canister while holding the release buttons indicated in the
illustration pressed by fingers.
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(2)Plug the disconnected end of hose D.
(3)Confirm that the evaporative emission system pressure pump (Miller number 6872A)
is operating properly. Perform the self-test as described in the pump manufacturer’s instructions.
(4)Remove the fuel cap.
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(5)Connect the evaporative emission system pressure pump (Miller number 6872A) to the fuel
tank filler tube by using fuel tank adapter (MLR-8382).
(6)Pressure test the system to determine whether any leaks are present.
| note |
The "Pressure test" in this procedure refers to the I/M240 Simulation Test. The
eight steps of this test are described in the manufacturer’s instructions for the evaporative
emission system pressure pump, Miller number 6872A.
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(7)Remove the evaporative emission system pressure pump (Miller number 6872A) and
the fuel tank adapter (MLR-8382), and reinstall the fuel cap.
(8)Connect hose D to the evaporative emission canister.
Q.
Is the evaporative emission system line free of leaks?
Go to Step 11 .
Go to Step 7 .
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STEP 7. Check for leaks in evaporative emission hoses D through E.
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(1)Use a hand vacuum pump to test each hose from hose D to hose E.
Q.
Do the hoses hold vacuum?
Go to Step 8 .
Replace any damaged hose. Then go to Step 13 .
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STEP 8. Check for leaks in evaporative emission hoses F and G.
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(1)Remove the fuel tank assembly
(2)Use a hand vacuum pump to test each hose F and G.
Q.
Do the hoses hold vacuum?
Go to Step 9 .
Replace any damaged hose. Then go to Step 13 .
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STEP 9. Check for leaks in evaporative emission hoses H and I.
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(1)Remove the fuel tank assembly.
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(2)Use a hand vacuum pump to test each hose H and I.
Q.
Does the hose hold vacuum?
Go to Step 10 .
Replace the hose and reinstall the fuel tank assembly. Then go to Step 13 .
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STEP 10. Check for leaks in the fuel tank.
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(1)Visually check for cracks or other leaks in the fuel tank.
| note |
Carefully check the fuel pump module and the fuel tank differential pressure sensor installation
in the fuel tank.
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(2)Connect the evaporative emission system pressure pump (Miller number 6872A) to the fuel
filler hose.
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(3)Plug the hose and the nipple shown in the illustration.
| note |
If these items are not securely plugged now, the fuel could leak in the next step.
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(4)Pressurize the fuel tank with the evaporative emission system pressure pump.
(5)In the pressurized state, check for leaks by applying a soapy water solution to
each section and look for bubbles.
Q.
Are any leaks found?
YES <When there is a leak from the attachment points of the fuel pump module, fuel
tank differential pressure sensor, fuel level sensor or leveling valve.> : Repair or replace the leaked parts and check again that there are no leaks. Then
reinstall the fuel tank. Then go to Step 13 .
YES <When there is a leak from the fuel tank.> : Replace the fuel tank. Go to Step 13 .
When there is no leak, reinstall the fuel tank. Then go to Step 11 .
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STEP 11. Check the evaporative emission canister for vacuum leaks.
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(1)Connect a hand vacuum pump to the evaporative emission canister and plug the other nipples.
(2)Apply a pressure on the hand vacuum pump, and confirm that air is maintained.
(3)Disconnect the hand vacuum pump and remove the plugs.
Q.
Is the evaporative emission canister in good condition?
Go to Step 12 .
Replace the evaporative emission canister. Then go to Step 13 .
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STEP 12. Using scan tool MB991958, check the evaporative emission
system monitor test.
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| caution |
- During this test, the ECM automatically increases
the engine speed to 1,600 r/min or greater. Check that the transaxle is set to "P"
position.
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the DTCs using scan tool MB991958.
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(3)Check that the fuel cap is securely closed (Tighten until three clicks are heard).
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(6)Select "Evap Leak Mon."
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(7)During the test, keep the accelerator pedal at the idle position.
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(8)Keep the engine speed and engine load within the specified range. When the monitor
test starts, the "In Progress" item on scan tool MB991958 will change from "NO" to "YES".
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(9)Turn the ignition switch to the "LOCK" (OFF) position.
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Q.
Is "Evap Leak Mon. Completed. Test Failed and DTCs Set" displayed on scan tool MB991958?
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Replace the ECM. When the ECM is replaced, register the ID code. Refer to GROUP
42B, Diagnosis - ID Code Registration Judgment Table <Vehicles with KOS> or
GROUP 42C, Diagnosis - ID Code Registration Judgment Table <Vehicles with WCM> .
Then go to Step 13 .
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NO <"Evap Leak Mon. Completed. Test Passed" is displayed on scan tool MB991958.> : The evaporative emission system is working properly at this time. Go to Step 13
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NO <"Evap Leak Mon. Discontinued. Retest again from the first" is displayed on scan
tool MB991958.> : The EVAP monitor has been interrupted during the test. Turn the ignition switch
to the "LOCK" (OFF) position once, and repeat the monitoring from Step 13 .
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STEP 13. Perform the OBD-II drive cycle.
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(1)Confirm the repair by performing the appropriate drive cycle (Refer to Diagnostic
Function - OBD-ll Drive Cycle - Pattern 5 ).
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Retry the troubleshooting.
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The inspection is complete.
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