DTC P2421: Inspection

EVAP Canister Vent Shut Valve Inspection (Open Stuck) 

Test Procedure 

• Procedure
  • Disconnect the fuel vent tube (A) and drain tube (B) from the EVAP canister (C), then connect the vacuum pump/gauge, 0-30 inHg (D) to the EVAP canister as shown.
  • Turn the vehicle to the ON mode.
  • Select the HDS [CVS ON].
  • Apply vacuum to the hose.

    NOTE:  Be careful not to exceed the vacuum. If you do, the EVAP canister vent shut valve can be damaged.

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

• Normal Conditions
  • Vacuum is held.

Results 

• If it is abnormal, there is a problem with the EVAP canister vent shut valve.

EVAP Purge System 1 Inspection (Blockage/Leakage) 

Test Procedure 

• Procedure
  • Check for a poor connection, a blockage, restriction, leakage, or any damage on the EVAP purge system component (A).

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

• Normal Conditions
  • Connection conditions are OK, and there is no blockage, restriction, leakage, or damage.

Results 

• If it is abnormal, there is a problem with EVAP purge system 1.

EVAP Canister Purge Valve Inspection (Close Stuck) 

Preconditions 

• EVAP purge system 1 is normal

Test Procedure 

• Procedure
  • Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect a vacuum pump/gauge, 0-30 inHg (C), to the EVAP canister purge valve as shown.
  • Turn the vehicle to the ON mode.
  • Select the HDS [PCS ON].
  • Apply pressure to the EVAP canister purge valve.

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

• Normal Conditions
  • Pressure is not held.

Results 

• If it is abnormal, there is a problem with the EVAP canister purge valve.

EVAP Purge System 2 Inspection (Blockage) 

Test Procedure 

• Procedure
  • Disconnect the purge tube (A) from the EVAP canister purge valve (B).
  • Disconnect the fuel purge pipe (C) from the EVAP canister (D).
  • Connect the hose (E) to the fuel purge pipe, then connect the vacuum pump/gauge, 0-30 inHg (F) to the hose as shown.
  • Apply pressure to the hose.

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

• Normal Conditions
  • Pressure is not held.

Results 

• If it is abnormal, there is a problem with EVAP purge system 2.

EVAP Purge System 2 Inspection (Leakage) 

Preconditions 

• EVAP canister purge valve is normal

Test Procedure 

• Procedure
  • Disconnect the fuel purge pipe (A) from the EVAP canister (B).
  • Connect the hose (C) to the fuel purge pipe, then connect the vacuum pump/gauge, 0-30 inHg (D) to the hose as shown.
  • Apply vacuum to the hose.

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

• Normal Conditions
  • Vacuum is held.

Results 

• If it is abnormal, there is a problem with EVAP purge system 2.

Main Flap Unit Inspection 

Test Procedure 

• Procedure
  • Check the shut-off valve (A) is closed, and inspect the flap seal of the shut-off valve (B) and the mating surface of the shut-off valve for missing or damage.

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

• Normal Conditions
  • The shut-off valve is closed, and there is no missing or damaged seals.

Results 

• If it is abnormal, there is a problem with the main flap unit.

Fuel Tank System Inspection (Leakage) 

Preconditions 

• Main flap unit is normal

Test Procedure 

• Procedure
  • Disconnect the fuel vent tube (A) from the EVAP canister (B).
  • Connect the hose (C) to the fuel vent tube, then connect a T-fitting (D), the vacuum/pressure gauge, 0-4 inHg (E), and a vacuum pump/gauge, 0-30 inHg (F), to the vacuum hose as shown.
  • Apply about 3.33 kPa (25 mmHg, 0.98 inHg) of vacuum to the fuel tank system.

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

• Normal Conditions
  • Vacuum is held.

Results 

• If it is abnormal, there is a problem with the fuel tank system.

FTP Sensor Inspection 

Test Procedure 

• Procedure
  • Disconnect the FTP sensor vent hose (A) from the FTP sensor (B).
  • Remove the FTP sensor from the EVAP canister (C) with its connector connected.
  • Turn the vehicle to the ON mode.
  • Confirm the HDS [FTP Sensor].

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

• Normal Conditions
  • HDS [FTP Sensor] indicates -0.67 kPa (-5.0 mmHg, -0.198 inHg) - 0.67 kPa (5.0 mmHg, 0.198 inHg)  .

Results 

• If it is abnormal, there is a problem with the FTP sensor.

EVAP Canister Inspection 

Test Procedure 

• If the other inspection item(s) indicated a normal condition, then it is determined that the remaining EVAP canister is the cause.

Results 

• There is a problem with the EVAP canister.