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DTC Descriptions

  1. DTC P0180: Fuel Temperature Sensor Circuit Malfunction

    Fuel tank temperature sensor circuit is monitored by PCM. DTC P0180 indicates an excessively high or low voltage was sent to PCM from fuel tank temperature sensor or a rationally incorrect voltage is sent to PCM, compared to voltage signals from Engine Coolant Temperature (ECT) sensor and Intake Air Temperature (IAT) sensor. Possible causes are as follows:
    • Fuel tank temperature sensor circuit is open or shorted.
    • Faulty fuel tank temperature sensor.

    For DTC P0180, fuel tank temperature sensor should have a resistance reading of 2.3-2.7 k/ohms at 68°F (20°C).

  2. DTC P0443: EVAP Emission Control System Purge Control Circuit Malfunction

    EVAP canister purge valve signal return circuit is monitored by PCM. DTC P0443 indicates an improper signal is sent to PCM through EVAP canister purge solenoid. Possible causes are as follows:
    • EVAP canister purge valve circuit shorted or open.
    • Faulty EVAP canister purge valve.

    For DTC P0443, when EVAP canister is commanded on 100 percent duty cycle, air should pass freely through 2 ports of EVAP canister purge valve.

  3. DTC P0443: EVAP Emission Control System Purge Control Circuit Malfunction

    EVAP canister purge valve signal return circuit is monitored by PCM. DTC P0443 indicates when an improper signal is sent to PCM through EVAP canister purge solenoid. Possible causes are as follows:
    • EVAP canister purge valve circuit shorted or open.
    • EVAP canister purge valve.

    For DTC P0443, when EVAP canister is commanded on 100 percent duty cycle air should pass freely through 2 ports of EVAP canister purge valve.

  4. DTC P0446: EVAP Emission Control System Vent Malfunction

    EVAP canister vent control solenoid signal return circuit is monitored by PCM. DTC P0446 indicates when an improper signal is sent to PCM through EVAP canister vent control solenoid. Possible causes are as follows:
    • EVAP canister vent control solenoid circuit shorted or open.
    • EVAP canister vent control solenoid.

    For DTC P0446, when EVAP canister is commanded on 100 percent duty cycle air should pass freely through 2 ports of EVAP canister purge valve.

  5. DTC P0450: EVAP Pressure Sensor Malfunction

    EVAP pressure sensor circuit is monitored by PCM. DTC P0450 indicates an improper voltage is sent to PCM from EVAP pressure sensor. Possible causes are as follows:
    • EVAP pressure sensor circuit is open or shorted.
    • Hoses to EVAP pressure sensor are disconnected or clogged.
    • Faulty EVAP pressure sensor.
    • Faulty EVAP canister vent control solenoid.
    • Faulty EVAP canister purge valve.
    • Faulty EVAP canister.
    • Damaged rubber hose from EVAP canister vent control solenoid to water separator.

  6. DTC P1444: EVAP Emission Control System Canister Purge Valve

    Camshaft Position (CMP) sensor, Mass Air Flow (MAF) sensor, Engine Coolant Temperature (ECT) sensor, ignition switch, Throttle Position (TP) sensor, idle switch, HO2S-11, Fuel Tank Temperature (FTT) sensor, and Vehicle Speed Sensor (VSS) circuits are monitored by PCM. DTC P1444 indicates when canister purge flow is detected during specified driving conditions, even when EVAP canister purge valve is completely closed. Possible causes are as follows:
    • Faulty EVAP pressure sensor.
    • EVAP canister purge valve is stuck open.
    • Faulty EVAP canister vent valve.
    • Damaged EVAP canister.
    • Hoses are incorrectly connected or clogged.

    For DTC P1444, remove vacuum line between EVAP canister and EVAP canister purge valve at EVAP canister purge valve. With ignition on and engine running at idle, no vacuum should be present at vacuum line.

  7. DTC P1446: EVAP Emission Control System Vent Control (Closed)

    EVAP pressure sensor circuit is monitored by PCM. DTC P1446 indicates when EVAP canister vent control solenoid remains closed under specified driving conditions. Possible causes are as follows:
    • Faulty EVAP canister vent control solenoid.
    • Faulty EVAP pressure sensor and circuit.
    • Blocked rubber tube to EVAP canister vent control solenoid.
    • Damaged water separator.
    • EVAP canister is saturated with water.

    For DTCP1446, disconnect EVAP canister vent control solenoid circuit connector. Air should pass freely through EVAP canister vent control solenoid.

  8. DTC P1447: EVAP Emission Purge Flow Monitoring Malfunction

    EVAP pressure sensor and MAP/BARO pressure sensor circuits are monitored by PCM. DTC P1447 indicates EVAP control system is not operating properly or when EVAP system has a leak between intake manifold and EVAP pressure sensor. Possible causes are as follows:
    • EVAP canister purge valve stuck closed.
    • Faulty EVAP pressure sensor and circuit.
    • Hoses are incorrectly connected or disconnected.
    • Blocked rubber tube to EVAP canister vent control solenoid.
    • Blocked or bent rubber tube to the MAP/BARO solenoid valve.
    • Cracked EVAP canister.
    • Faulty EVAP canister purge valve or circuit.
    • Closed throttle position switch.
    • Blocked purge port.
    • Faulty EVAP canister vent valve.

    For DTC P1447, disconnect vacuum between EVAP canister purge valve and EVAP canister from EVAP canister. With ignition on, engine running and EVAP canister purge valve commanded on 100 percent, manifold vacuum should be observed at disconnected vacuum line.

  9. DTC P1448: EVAP Emission Control System Vent Control (Open)

    EVAP pressure sensor circuit is monitored by PCM. DTC P1448 indicates EVAP canister vent control solenoid remains opened under specified driving conditions. Possible causes are as follows:
    • Faulty EVAP canister vent control solenoid.
    • Faulty EVAP pressure sensor and circuit.
    • Blocked rubber tube to EVAP canister vent control solenoid.
    • Damaged water separator.
    • EVAP canister is saturated with water.
    • Faulty vacuum cut valve.

    For DTC P1448, with battery voltage applied to EVAP canister vent control solenoid, air should not pass through EVAP canister vent control solenoid.

  10. DTC P1490: EVAP Emission Vacuum Cut By-Pass Solenoid Circuit Malfunction

    EVAP emission system vacuum cut by-pass solenoid signal return circuit is monitored by PCM. DTC P1490 indicates improper voltage signal is sent to PCM through EVAP emission system vacuum cut by-pass solenoid. Possible causes are as follows:
    • EVAP emission system vacuum cut by-pass solenoid circuit is open, or shorted to GND or PWR.
    • EVAP emission system vacuum cut by-pass solenoid.

    For DTC P1490, check vacuum cut by-pass solenoid circuit harness and connections.

  11. DTC P1491: EVAP Emission Vacuum Cut By-Pass Solenoid Malfunction

    EVAP system pressure sensor circuit is monitored by PCM. DTC P1491 indicates EVAP emission system vacuum cut by-pass solenoid does not operate properly. Possible causes are as follows:
    • Faulty vacuum cut valve by-pass valve.
    • Faulty vacuum cut valve.
    • By-pass hoses may be clogged.
    • EVAP control system pressure sensor and circuit.
    • EVAP canister vent control solenoid.
    • Hose between fuel tank and vacuum cut valve clogged.
    • Hose between vacuum cut valve and EVAP canister clogged.
    • Damaged EVAP canister.
    • Check EVAP purge port of fuel tank for clogging.

    For DTC P1491, disconnect circuit harness and vacuum lines from EVAP emission system vacuum cut by-pass solenoid, air should not pass through EVAP emission system vacuum cut by-pass solenoid.

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