P0441

DTC P0441 EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT PURGE FLOW

CIRCUIT DESCRIPTION

DTC Detection Conditions:

The vapor pressure sensor, VSV for CCV (Vacuum Switching Valve for Canister Closed Valve), and VSV for EVAP (Evaporative Emission) are used to detect abnormalities in the EVAP control system.

The ECM determines whether there is an abnormality in the EVAP control system based on the vapor pressure sensor signal.

DTCs P0441 and P0446 are set by the ECM when evaporative emissions leak from the components within the dotted line in Fig. 1, and when there is a malfunction in either VSV for EVAP and VSV for CCV, or in the vapor pressure sensor itself.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Monitor Result (Mode 06 Data):

The ECM checks the EVAP (Evaporative Emission) system using the vapor pressure sensor, CCV (Canister Closed Valve), and VSV (Vacuum Switching Valve) for EVAP. The ECM closes the EVAP system and introduces negative pressure (a vacuum) into it. The ECM then monitors the internal pressure using the vapor pressure sensor.

The VSV for EVAP is used to discharge the evaporative emissions from the fuel tank into the intake manifold via the canister. In addition, it creates negative pressure (a vacuum) inside the fuel tank simultaneously with the operation of the VSV for CCV to conduct leak tests.

P0441
DTC P0441 is set if either one of the following conditions applies:
- VSV for EVAP stuck closed malfunction:
The ECM checks for the malfunction by signaling the VSV for EVAP to open with the VSV for CCV (vent) closed. If a highly negative pressure does not develop in the fuel tank, the ECM determines that the VSV for EVAP remains closed and illuminates the MIL and sets the DTC.

- VSV for EVAP stuck open malfunction:
The ECM checks for the malfunction by signaling both the VSV for EVAP and VSV for CCV to close at a time when the internal fuel tank pressure level is equal to the atmospheric pressure. If a highly negative pressure develops in the fuel tank at this early stage of the check, the ECM determines that the VSV for EVAP is stuck open, and illuminates the MIL and sets the DTC.

CONFIRMATION READINESS TEST

First Trip Procedures
a. The engine must be cold, and the ambient temperature must be approximately between 10°C and 35°C (50°F and 95°F).
b. The intake air temperature and the engine coolant temperature are almost equal.

c. Clear DTCs.
Disconnect the battery terminal or remove the EFI fuse for more than 60 seconds.
READINESS TESTS will show INCMPL (incomplete).

d. Drive the vehicle on a freeway. Write down the initial status of the READINESS TESTS. As each Readiness Test passes EVAP evaluation monitors, its status will change to COMPL (complete). This procedure may take approximately 20 minutes or more.

NOTE: Do not shut off the engine - the results will be invalid.

Pass Condition - No Problem Found by the ECM
When the EVAP EVAL shows COMPL, go to the Non-Continuous Tests screen.

NOTE: Do not shut off the engine - the results will be invalid.

- To enter the Non-Continuous Tests screen, go to ENHANCED OBD II, Onboard Tests, Non-continuous Tests.
- If all of the tests in the Time $02 category show Pass, the EVAP Evaluation Monitor has operated and no problem was detected.

Fail Condition - Problem Detected by the ECM
If the EVAP EVAL shows INCMPL, go to the Non-Continuous Test screen.

1. If all of the Tests show Pass, the following may have occurred.
- The EVAP Evaluation Monitor did not operate.
- The EVAP Evaluation Monitor has not yet been finished.
- The ECM has not yet finished the judgement process.

2. If one or more of the tests in the Time $02 category show Fail, the EVAP Evaluation Monitor did operate and the ECM has detected a problem.

3. Go to Continuous Tests screen. This is the only place DTC's are listed for the first trip.

NOTE: The DTC listed may not be valid. A second trip is needed to confirm the DTC.

Second Trip Procedures

e. The engine must be cold, and the ambient temperature must be approximately between 10°C and 35°C (50°F and 95°F).
f. Go to the READINESS TESTS screen.
g. Drive the vehicle on a freeway. Write down the initial status of the READINESS TESTS. This procedure may take approximately 20 minutes or more.

NOTE: Do not shut off the engine - the results will be invalid.

h. If the READINESS TESTS change to COMPL, the EVAP evaluation monitor has operated. Check for any stored DTCs.
- If a DTC was stored, the problem has been detected and confirmed by the ECM.
- If no DTC was found, the EVAP monitor operated but no problem was detected.

Wiring Diagram:

INSPECTION PROCEDURE

HINT:
- If any of DTC P0441, P0446 or P0451 are set simultaneously with DTC P0442 or P0456, first troubleshoot DTC P0441, P0446 or P0451. If no malfunction is detected, troubleshoot DTC P0442 or P0456 next.
- Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.
- When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the vapor pressure sensor.