P1457

DTC P1457: EVAP Control System Leakage (EVAP canister system)

NOTE: 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.

Special Tools Required
Vacuum Pump/Gauge, 0 - 30 in.Hg A973X-041-XXXXX

Please note that this is a 2 trip code, once cleared, they cannot be reproduced in 1 trip. Also, certain specific driving and ambient conditions must occur before the PCM will complete the system checks. Additional test drives may still not meet the specific conditions needed to reproduce the codes.

Therefore, follow these troubleshooting procedures carefully +0 ensure the integrity of the system and to confirm the cause of the problem or code.

NOTE: Fresh fuel has a higher volatility that will create greater pressure/vacuum. The optimum condition for testing is fresh fuel, at least half less than a full tank. 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.

EVAP Canister Purge Valve Test

1. Disconnect the vacuum hose from the EVAP canister purge valve (A), and connect a vacuum pump to the hose.




2. Apply vacuum to the hose.

Does the valve hold vacuum?

YES - Go to step 3.

NO - Replace the EVAP canister purge valve. If the valve is contaminated with charcoal particles, replace the canister, and blow out the hoses.




3. Connect PCM connector terminal A6 to body ground with a jumper wire.
4. Turn the ignition switch ON (II).
5. Apply vacuum to the hose.

Does the valve hold vacuum?

YES - Go to step 6.

NO - EVAP canister purge valve is OK. Go to step 11.

6. Turn the ignition switch OFF.
7. Disconnect the EVAP canister purge valve 2P connector.




8. Check for continuity between EVAP canister purge valve 2P connector terminal No.2 and body ground.

Is there continuity?

YES - Go to step 9.

NO - Repair open in the wire between the EVAP canister purge valve and PCM (A6).

9. Turn the ignition switch ON (II).




10. Measure voltage between EVAP canister purge valve 2P connector terminal No.1 and body ground.

Is there battery voltage?

YES - Replace the EVAP canister purge valve.

NO - Repair open in the wire between the EVAP canister purge valve and No.6 ECU (PCM) CRUISE CONTROL (15A) fuse.

EVAP Bypass Solenoid Valve Test




11. Disconnect the vacuum hose from EVAP two way valve (A), and connector a vacuum pump to the hose.
12. Turn the ignition switch ON (II).
13. Apply vacuum to the hose.

Does the valve hold vacuum?

YES - EVAP bypass solenoid valve/EVAP two way valve is OK. Go to step 19.

NO - Go to step 14.

14. Turn the ignition switch OFF.
15. Disconnect the EVAP bypass solenoid valve 2P connector.







16. Check for continuity between EVAP bypass solenoid valve 2P connector terminal No.2 and body ground.

Is there continuity?

YES - Go to step 17.

NO - Replace the EVAP bypass solenoid valve (A) and O-rings (B).

17. Disconnect the PCM connector A (32P).




18. Check for continuity between EVAP bypass solenoid valve 2P connector terminal No.2 and body ground.

Is there continuity?

YES - Replace short in the wire between the EVAP bypass solenoid valve and PCM (A3).

NO - Substitute a known-good PCM and recheck. If the symptom/indication goes away, replace the original PCM.

EVAP Canister Vent Shut Valve Test




19. Disconnect the vacuum hose from the EVAP canister vent filter (A), and connect a vacuum pump to the hose.




20. Connect PCM connector terminal A4 to body ground with a jumper wire.
21. Turn the ignition switch ON (II)
22. Apply vacuum to the hose.

Does the valve hold vacuum?

YES - EVAP canister vent shut valve is OK. Go to step 28.

NO - Go to step 23.

23. Turn the ignition switch OFF.
24. Disconnect the EVAP canister vent shut valve 2P connector.




25. Check for continuity between EVAP canister vent shut valve 2P connector terminal No.2 and body ground.

Is there continuity?

YES - Go to step 26.

NO - Repair open in the wire between the EVAP canister vent shut valve and PCM (A4).

26. Turn the ignition switch ON (II).




27. Measure voltage between EVAP canister vent shut valve 2P connector terminal No.1 and body ground.

Is there battery voltage?

YES - Replace the EVAP canister vent shut valve (A) and O-ring (B).

NO - Repair open in the wire between the EVAP canister vent shut valve and No.6 ECU (PCM) CRUISE CONTROL (15A) fuse.

Canister System Leak Test

28. Turn the ignition switch OFF.




29. Connect two three-way T-fittings (A) into the hose from the EVAP canister to the EVAP two way valve. Connect the FTP sensor to one of the T-fittings and the vacuum pump to the other.




30. Remove the vent hose from the EVAP canister vent shut valve (A) and cap (B) the port to seal the fresh air vent for the EVAP canister.
31. Turn the ignition switch ON (II).
32. While monitoring the FTP sensor voltage with the Honda PGM Tester, or measuring voltage between PCM connector terminals A29 and C18 slowly pump the vacuum pump.
33. Continue to pump vacuum until the voltage drops to about 1.5 V. Make sure that the engine coolant temperature still above 95 °F (35 °C) and your vacuum pump has no leak.
34. Check the voltage for 20 seconds.

Does the voltage drop to 1.5 V and hold for at least 20 seconds?

YES - Inspect the EVAP canister vent shut valve line and connections.

NO - Go to step 35.

35. Turn the ignition switch OFF.




36. Disconnect the quick-connect fitting (A) from the EVAP canister and plug (B) the canister port.
37. Turn the ignition switch ON (II).
38. While monitoring the FTP sensor voltage with the Honda PGM Tester, or measuring voltage between PCM connector terminals A29 and C18 slowly pump the vacuum pump.
39. Continue to pump vacuum until the voltage drops to about 1.5 V. Make sure the engine coolant temperature is still above 95 °F (35 °C) and your vacuum pump has no leak.
40. Check that voltage for 20 seconds.

Does the voltage drop to 1.5 V and hold for at least 20 seconds?

YES - Inspect the fuel tank vapor vent tube and connections.

NO - Go to step 41.

41. Turn the ignition switch OFF.




42. Disconnect the purge line hose (A) from the canister at the metal line and plug (B) the hose.
43. Turn the ignition switch ON (II).
44. While monitoring the FTP sensor voltage with the Honda PGM Tester, or measuring voltage between PCM connector terminals A29 and C18 slowly pump the vacuum pump.
45. Continue to pump vacuum until the voltage drops to about 1.5 V. Make sure that the engine coolant temperature still above 95 °F (35 °C) and your vacuum pump has no leak.
46. Monitor that check the voltage for 20 seconds.

Does the voltage drop to 1.5 V and hold for at least 20 seconds?

YES - Inspect EVAP canister purge valve line and connections. If they are OK, perform the EVAP two way valve test, and fuel tank vapor control valve test.

NO - Replace the EVAP canister, and repeat step 43 through 46. If the system holds vacuum, the repair is complete.

DTC P1457 Still Set? Test For Internal Leaks

Leak Testing For DTC P1457

1. Turn the ignition switch ON (II).
2. Clamp the vacuum hose between the EVAP two-way vale and the fuel tank.
3. Disconnect the vacuum hose between the EVAP canister and the two-way valve at the two-way valve port.
4. Attach a hand vacuum pump to the port on the two-way valve. Use the PGM tester to read the FTP sensor voltage. Record the reading.
5. Apply 2 inches of vacuum to the two-way valve, and watch the FTP sensor voltage. If the voltage drops more than 0.05 V in 20 seconds, replace the two-way valve and the bypass solenoid valve, and retest.