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DTC P1456 Or P1457: EVAP Control System

NOTE: DTC P1456 = EVAP Control System Leak Detected (Fuel Tank System) DTC P1457 = EVAP Control System Leak Detected (EVAP Control Canister System)
  1. If either DTC P1456 or DTC P1457 sets check for:
    • A faulty fuel filler cap.
    • Proper vacuum connections.
    • Fuel tank leak.
    • EVAP control canister vent shut valve malfunction.
    • EVAP control canister vent shut valve circuit malfunction.
    • EVAP purge control solenoid valve malfunction.
    • EVAP purge control solenoid valve circuit malfunction.
    • EVAP by-pass solenoid valve malfunction.
    • EVAP by-pass solenoid valve circuit malfunction.
    • Fuel tank pressure sensor malfunction.
    • Fuel tank pressure sensor circuit malfunction.
    • EVAP control canister malfunction.

    Repair as necessary. If no problems are found, go to next step.

  2. Disconnect vacuum hose from EVAP 3-way valve located on side of EVAP canister. Turn ignition on. Connect vacuum pump to hose and apply vacuum (about 5 pump strokes) to EVAP control canister vent shut valve. If vacuum holds, go to next step. If vacuum does not hold, go to step 4).
  3. Disconnect EVAP control canister vent shut valve 2-pin connector located on top of EVAP control canister. Apply vacuum to EVAP control canister vent shut valve. If vacuum holds, replace EVAP control canister vent shut valve. If vacuum does not hold, repair short in Orange/Green wire between EVAP control canister vent shut valve and PCM 32-pin connector terminal No. 4.
  4. Turn ignition off. Backprobing, connect a fused jumper wire between PCM 32-pin connector terminal No. 4 (Orange/Green wire) and ground. Turn ignition on. Apply vacuum to EVAP control canister vent shut valve. If vacuum does not hold, go to next step. If vacuum holds, go to step 7).
  5. Turn ignition off. Disconnect EVAP control canister vent shut valve 2-pin connector. Turn ignition on. Measure voltage between ground and EVAP control canister vent shut valve 2-pin harness connector terminal No. 1 (Black/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between EVAP control canister vent shut valve and ECU, EAT ECU, CRUISE CONTROL, FAN TIMER (7.5-amp) fuse No. 4, located in underdash fuse/relay box.
  6. Turn ignition off. Reconnect EVAP control canister vent shut valve 2-pin connector. Turn ignition on. Backprobing, measure voltage between PCM 32-pin connector terminals No. 4 (Orange/Green wire) and PCM 25-pin connector terminal No. 2 (Black wire). If battery voltage is present, replace EVAP control canister vent shut valve. If battery voltage is not present, repair open in Orange/Green wire between EVAP control canister vent shut valve and PCM 32-pin connector terminal No. 4.
  7. Disconnect EVAP control canister lower vacuum hose. See Fig 1. Connect vacuum gauge to hose. Start cold engine and allow to idle. Ensure engine coolant temperature is less than 149°F (65°C). Quickly increase engine speed to 3000 RPM and check for vacuum at EVAP control canister lower vacuum hose. If vacuum is present, go to next step. If vacuum is not present, go to step 10).
  8. Disconnect EVAP purge control solenoid valve 2-pin connector. Quickly increase engine speed to 3000 RPM and check for vacuum at EVAP control canister lower vacuum hose. See Fig 1. If vacuum is not present, go to next step. If vacuum is present, check for incorrect vacuum hose routing. If hose routing is okay, replace EVAP purge control solenoid valve.
  9. Turn ignition off. Disconnect PCM 32-pin connector. Check for continuity between ground and EVAP purge control solenoid valve 2-pin harness connector terminal No. 1 (Red/Yellow wire). If continuity exists, repair short in Red/Yellow wire between EVAP purge control solenoid valve and PCM 32-pin connector terminal No. 6. If continuity does not exist, substitute a known-good PCM and recheck. If DTCs do not reset, replace original PCM.
  10. Start engine and hold at 3000 RPM with no load and transmission in Park or Neutral, until cooling fan comes on. Allow engine to idle and check for vacuum at EVAP control canister lower vacuum hose. Quickly increase engine speed to 3000 RPM and check for vacuum at EVAP control canister lower vacuum hose again. If vacuum is not present, go to next step. If vacuum is present, go to step 14).
  11. Turn ignition off. Disconnect EVAP purge control solenoid valve 2-pin connector. Start engine. Measure voltage between EVAP purge control solenoid valve 2-pin harness connector terminals. If battery voltage is not present, go to next step. If battery voltage is present, ensure vacuum hose routing is correct. If vacuum hoses are okay, replace EVAP purge control solenoid valve.
  12. Measure voltage between ground and EVAP purger control solenoid valve 2-pin harness connector terminal No. 2 (Black/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between EVAP purger control solenoid valve and ECU, EAT ECU, CRUISE CONTROL, FAN TIMER (7.5-amp) fuse No. 4.
  13. Turn ignition off. Reconnect EVAP purge control solenoid valve 2-pin connector. Turn ignition on. Backprobing, measure voltage between PCM 32-pin connector terminal No. 6 (Red/Yellow wire) and PCM 25-pin connector terminal No. 2 (Black wire). If battery voltage is not present, repair open in Red/Yellow wire between EVAP purge control solenoid valve 2-pin connector and PCM 32-pin connector. If battery voltage is present, substitute a known-good PCM and recheck. If DTCs do not reset, replace original PCM.
  14. Ensure EVAP 2-way valve is operating properly. See SYSTEM/COMPONENT TESTS article. If EVAP 2-way valve is operating properly, go to next step. If EVAP 2-way is not operating properly, replace EVAP 2-way valve.
  15. Disconnect both vacuum hoses from EVAP 2-way valve. See Fig 2. Connect a vacuum pump to lower port. Turn ignition on. Apply vacuum to EVAP 2-way valve lower vacuum port. If vacuum holds, go to next step. If vacuum does not hold, disconnect EVAP by-pass solenoid valve 2-pin connector and recheck vacuum. If vacuum still does not hold, replace EVAP by-pass solenoid valve. If vacuum holds, repair short in Blue/Black wire between EVAP by-pass solenoid valve and PCM 32-pin connector terminal No. 3.
  16. Turn ignition off. Backprobing, connect fused jumper wire between PCM 32-pin connector terminal No. 3 (Blue/Black wire) and ground. Turn ignition on. If EVAP by-pass solenoid valve holds vacuum, go to next step. If EVAP by-pass solenoid valve does not hold vacuum, check for leaks to atmosphere, and repair or replace following components if needed:
    • Fuel filler cap and fuel tank.
    • Fuel vapor line.
    • EVAP 2-way valve.
    • EVAP by-pass solenoid valve.
    • Fuel tank pressure sensor.
    • EVAP control canister.
    • EVAP control canister vent shut valve.
    • EVAP purge control solenoid valve.
    • Vacuum hoses and connections.

      Turn ignition off. Disconnect EVAP by-pass solenoid valve 2-pin connector. Turn ignition on. Measure voltage between ground and EVAP by-pass solenoid valve 2-pin harness connector terminal No. 1 (Black/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Black/Yellow wire between EVAP bypass solenoid valve and ECU, EAT ECU, CRUISE CONTROL, FAN TIMER (7.5-amp) fuse No. 4.

  17. Turn ignition off. Reconnect EVAP by-pass solenoid valve 2-pin connector. Turn ignition on. Backprobing, measure voltage between PCM 32-pin connector terminal No. 3 (Blue/Black wire) and PCM 25-pin connector terminal No. 2 (Black wire). If battery voltage is present, replace EVAP by-pass solenoid valve. If battery voltage is not present, repair open in Blue/Black wire between EVAP by-pass solenoid valve and PCM 32-pin connector terminal No. 3.
    Fig 1: Identifying EVAP Control Canister Components
    G97H06005Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 2: Identifying EVAP 2-Way & By-Pass Solenoid Valves
    G97J06006Courtesy of AMERICAN HONDA MOTOR CO., INC.
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