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DTC P04F1

DTC P04F1  : EVAP System Low Purge Flow Detected

Special Tools Required 

Vacuum Pump/Gauge, 0-30 inHg Snap-on YA4000A or equivalent, commercially available 

Vacuum/Pressure Gauge, 0-4 inHg 07JAZ-001000B 

NOTE: Before you troubleshoot, review the general troubleshooting information .
DTC Description Confirmed DTC Pending DTC
P04F1 EVAP System Low Purge Flow Detected    

DTC (PGM-FI)

  1. Problem verification

    -1. Turn the vehicle to the ON mode.

    -2. Clear the DTC with the HDS.

    -3. Select the EVAP TEST in the Function Test Menu, then select the FUNCTION TEST with the HDS.

    EVAP TEST

    Is the result OK?

    YES 

    Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot .

    NO 

    The failure is duplicated. Go to step 2.

  2. EVAP canister purge line visual check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Check for a poor connection, a blockage, or damage at the EVAP canister purge line between the throttle body and the EVAP canister.

    Is the line OK?

    YES 

    Go to step 3.

    NO 

    Reconnect or repair the EVAP canister purge line.

  3. Determine possible failure area (EVAP canister purge valve, others)

    -1. Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect a T-fitting (C), a vacuum gauge, and a vacuum pump/gauge, 0-30 inHg (D), to the vacuum hose as shown.

    GHH385148Courtesy of HONDA, U.S.A., INC.

    -2. Turn the vehicle to the ON mode.

    -3. Select the EVAP TEST in the Function Test Menu, then select the PCS ON in the SINGLE SOLENOID with the HDS.

    EVAP TEST

    Apply about 2 kPa (0.6 inHg, 15 mmHg) of vacuum to the hose.

    Does it hold vacuum?

    YES 

    Replace the EVAP canister purge valve .

    NO 

    Go to step 4.

  4. Determine possible failure area (EVAP canister purge line, others)

    -1. Select the EVAP TEST in the Function Test Menu, then select the PCS OFF in the SINGLE SOLENOID with the HDS.

    EVAP TEST

    Reconnect the vacuum hose to the EVAP canister purge valve.

    -3. Disconnect the EVAP canister purge line (A) from the EVAP canister (B). Connect the T-fitting (C), the vacuum gauge, and the vacuum pump/gauge, 0-30 inHg (D), to the EVAP canister purge line as shown.

    GHH385149Courtesy of HONDA, U.S.A., INC.

    -4. Apply about 2 kPa (0.6 inHg, 15 mmHg) of vacuum to the hose.

    -5. Select the EVAP TEST in the Function Test Menu, then select the PCS ON in the SINGLE SOLENOID with the HDS.

    EVAP TEST

    Does it hold vacuum?

    YES 

    Check for a blockage in the purge line between the EVAP canister purge valve and the EVAP canister.

    NO 

    Go to step 5.

  5. FTP sensor performance check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Remove the FTP sensor with its connector connected .

    -3. Connect the T-fitting (A) to the vacuum gauge and the vacuum pump/gauge, 0-30 inHg (C), to the FTP sensor (B) as shown.

    GHH385150Courtesy of HONDA, U.S.A., INC.

    -4. Turn the vehicle to the ON mode.

    -5. Check and record the FTP sensor reading in the DATA LIST with the HDS.

    Signal Current conditions
    Values Unit
    FTP SENSOR    

    -6. Slowly apply about 1.3 kPa (0.38 inHg, 10 mmHg) of vacuum to the hose.

    NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.

    -7. Check the FTP SENSOR in the DATA LIST with the HDS.

    Signal Current conditions
    Values Unit
    FTP SENSOR    

    Does the value change?

    YES 

    Go to step 6.

    NO 

    Replace the FTP sensor .

  6. EVAP canister purge line check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Reconnect the EVAP canister purge line to the EVAP canister, and reinstall the FTP sensor .

    -3. Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect the T-fitting (C), the vacuum gauge, and the vacuum pump/gauge, 0-30 inHg (D), to the vacuum hose as shown.

    GHH385151Courtesy of HONDA, U.S.A., INC.

    -4. Select the EVAP TEST in the Function Test Menu, then select the PCS ON in the SINGLE SOLENOID with the HDS.

    EVAP TEST

    Slowly apply about 2 kPa (0.6 inHg, 15 mmHg) of vacuum to the hose.

    Does the hose hold vacuum?

    YES 

    Check for a blockage at the EVAP canister purge line port.

    NO 

    Replace the EVAP leak check module .