DTC P0456: EVAP System Very Small Leak Detected (USA and Canada models) (2013-15)

Special Tools Required 

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

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

The fuel system is designed to allow specified maximum vacuum and pressure conditions. Do not deviate from the vacuum and pressure tests as indicated in these procedures. Excessive pressure/vacuum would damage the EVAP components or cause eventual fuel tank failure.

NOTE: 

• Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems (2013-15), or How to Troubleshoot the A/T System (2013-15) .
• Fresh fuel has a higher volatility that will create greater pressure/vacuum. The best condition for testing is less than a full tank of fresh fuel. If possible, to assist in leak detection, add 1 gallon of fresh fuel to the tank (as long as it will not fill the tank), just before starting these procedures.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P0456 EVAP System Very Small Leak Detected

DTC (PGM-FI)

1. Fuel fill cap installation check:

   Check the fuel fill cap (the cap must say TIGHTEN TO CLICK). It should turn 1/4 turn after it's tight, then it clicks.

   Is the correct fuel fill cap installed and properly tightened?

   YES 

   Go to step 2.

   NO 

   Replace the fuel fill cap or tighten the cap, then do the repair verification.

2. Fuel fill cap seal and fuel fill pipe mating surface check:

   Check the fuel fill cap seal (A) and the fuel fill pipe mating surface (B). Verify that the fuel fill cap tether cord (C) is not caught under the cap.

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

   Is the fuel fill cap seal missing or damaged, is the fuel fill pipe damaged, or is the tether cord caught under the cap?

   YES 

   Replace the fuel fill cap or tighten the cap, then do the repair verification.

   NO 

   The fuel fill cap and the fuel fill pipe are OK. Go to step 3.

3. Problem verification:

   Press the engine start/stop button to select the ON mode.

   - 2. Clear the DTC with the HDS - Refer to: How to Troubleshoot the Fuel and Emissions Systems (2013-15), or How to Troubleshoot the A/T System (2013-15) .

   Clear DTC

   - 3. Select the EVAP TEST in the INSPECTION MENU, and do the FUNCTION TEST with the HDS.

   FUNCTION 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, the EVAP canister vent shut valve, and the PCM.

   NO 

   The failure is duplicated. Go to step 4.

4. Fuel tank vapor recirculation tube visual check:

   Press the engine start/stop button to select the OFF mode.

   - 2. Check for a poor connection or damage at the fuel tank vapor recirculation tube.

   Is the tube OK?

   YES 

   The tube is OK. Go to step 5.

   NO 

   Replace the fuel tank vapor recirculation tube, or replace the fuel tank if needed, then do the repair verification.

5. Determine possible failure area (EVAP canister vent shut valve, others):

   Disconnect the fuel tank vapor control valve hose (A) and the fresh air hose (B) from the EVAP canister (C), and plug the EVAP canister ports (D).

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

   - 2. Disconnect the vacuum hose (engine side) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect a vacuum pump/gauge, 0-30 inHg, to the purge control solenoid valve as shown.

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

   - 3. Press the engine start/stop button to select the ON mode.

   - 4. Select EVAP TEST in the INSPECTION MENU, and do the EVAP PCS ON and EVAP CVS ON in the MULTI SOLENOIDS with the HDS.

   MULTI SOLENOIDS

   - 5. Apply vacuum to the hose until the FTP reads 1.90 V (-0.59 inHg, -15.1 mmHg).

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

   Signal	Current conditions
   	Values	Unit
   FTP SENSOR

   - 6. Do the EVAP PCS OFF and EVAP CVS ON in the MULTI SOLENOIDS with the HDS, then remove the vacuum pump/gauge from the purge control solenoid valve.

   MULTI SOLENOIDS

   - 7. Check the parameter(s) below with the HDS for 1 minute.

   Signal	Current conditions
   	Values	Unit
   FTP SENSOR

   Does the voltage increase more than 0.2 V (0.1 inHg, 2.5 mmHg)?

   YES 

   Go to step 6.

   NO 

   Go to step 8.

6. EVAP canister purge line leak check:

   Reconnect the vacuum hose (A) (engine side) to the EVAP canister purge valve.

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

   - 2. Disconnect the vacuum hose (EVAP canister side) (B) from the EVAP canister purge valve (C) in the engine compartment, then connect the vacuum pump/gauge to the vacuum hose (EVAP canister side) as shown.

   - 3. Press the engine start/stop button to select the ON mode.

   - 4. Apply vacuum to the hose until the FTP reads 1.90 V (-0.59 inHg, -15.1 mmHg).

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

   Signal	Current conditions
   	Values	Unit
   FTP SENSOR

   - 5. Check the parameter(s) below with the HDS for 1 minute.

   Signal	Current conditions
   	Values	Unit
   FTP SENSOR

   Does the voltage increase more than 0.2 V (0.1 inHg, 2.5 mmHg)?

   YES 

   Go to step 7.

   NO 

   The EVAP canister purge line is OK. Replace the EVAP canister purge valve , then do the repair verification.

7. EVAP canister purge line visual check:

   Check for a loose or damaged EVAP canister purge line between the EVAP canister and the EVAP canister purge valve. Also check for a leaking EVAP canister.

   Are the line and the canister OK?

   1. YES 

      Replace these parts, then do the repair verification.

      • FTP sensor O-ring
      • EVAP canister vent shut valve case and O-ring
      • EVAP canister

      NO 

      Reconnect or repair the EVAP canister purge line, then do the repair verification.

8. EVAP canister vent shut valve operation check:

   Reconnect the fresh air hose (A) from the EVAP canister (B).

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

   - 2. Reconnect the vacuum hose (engine side) to the EVAP canister purge valve.

   - 3. Disconnect the vacuum hose (EVAP canister side) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect the vacuum pump/gauge to the purge control solenoid valve as shown.

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

   - 4. Select EVAP TEST in the INSPECTION MENU, and do the EVAP CVS ON in the SINGLE SOLENOID with the HDS.

   SINGLE SOLENOID

   - 5. Apply vacuum to the hose until the FTP reads 1.90 V (-0.59 inHg, -15.1 mmHg).

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

   Signal	Current conditions
   	Values	Unit
   FTP SENSOR

   - 6. Check the parameter(s) below with the HDS for 1 minute.

   Signal	Current conditions
   	Values	Unit
   FTP SENSOR

   Does the voltage increase more than 0.2 V (0.1 inHg, 2.5 mmHg)?

   YES 

   Replace the EVAP canister vent shut valve , then do the repair verification.

   NO 

   The EVAP canister vent shut valve is OK. Go to step 9.

9. Fuel fill pipe and fuel vapor return pipe visual check:

   Do the EVAP CVS OFF in the SINGLE SOLENOID with the HDS.

   SINGLE SOLENOID

   - 2. Check for looseness or damage at the fuel fill pipe and the fuel vapor return pipe.

   Are the parts OK?

   YES 

   The fuel fill pipe and the fuel vapor return pipe are OK. Check the fuel tank unit base gasket and the fuel tank, then do the repair verification.

   NO 

   Repair or replace the damaged parts, then do the repair verification.

10. Repair verification:

    Press the engine start/stop button to select the OFF mode.

    - 2. Install the parts in the reverse order of removal.

    - 3. Press the engine start/stop button to select the ON mode.

    - 4. Reset the PCM with the HDS - Refer to: How to Troubleshoot the Fuel and Emissions Systems (2013-15), or How to Troubleshoot the A/T System (2013-15) .

    Reset PCM

    - 5. Do the PCM idle learn procedure .

    - 6. Select the EVAP TEST in the INSPECTION MENU, and do the FUNCTION TEST with the HDS.

    FUNCTION TEST

    Is the result OK?

    YES 

    Troubleshooting is complete.

    NO 

    Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, the EVAP canister vent shut valve, and the PCM, then go to step 1.