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

This is a two-trip code; once cleared, it cannot be reproduced in one 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 code.

Follow these troubleshooting procedures carefully to ensure the integrity of the system and to confirm the cause of the problem or code.

NOTE: Fresh fuel has a high volatility that creates greater pressure/vacuum. The optimum condition for testing is fresh fuel, at least half, but 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 10 in.Hg (250 mmHg) of 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 EVAP canister, and blow out the hoses.





3. Turn the EVAP canister purge valve on with the Honda PGM Tester, or 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 - The 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. Turn the ignition switch ON (II).





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

Is there continuity?

YES - Go to step 10.

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





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 the No.6 ECU (PCM) CRUISE CONTROL (15 A) fuse.

EVAP Bypass Solenoid Valve Test
11. Remove the EVAP canister cover.





12. Disconnect the vacuum hose from the EVAP two way valve (A), and connect a vacuum pump to the canister port on the two way valve.
13. Turn the ignition switch ON (II).
14. Apply vacuum to the hose.

Does the valve hold vacuum?

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

NO - Go to step 15.

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





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

Is there continuity?

YES - Go to step 18.

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

18. Disconnect PCM connector A (32P).





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

Is there continuity?

YES - Repair the short in the wire between the EVAP bypass solenoid valve and the 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





20. Disconnect the vacuum hose from the EVAP canister vent filter tube, and connect a vacuum pump to the hose.





21. Turn the EVAP canister vent shut valve on with the Honda PGM Tester, or connect PCM connector terminal A4 to body ground with a jumper wire.
22. Turn the ignition switch ON (II)
23. Apply vacuum to the hose.

Does the valve hold vacuum?

YES - The EVAP canister vent shut valve is OK. Go to step 29.

NO - Go to step 24.

24. Turn the ignition switch OFF.
25. Disconnect the EVAP canister vent shut valve 2P connector.
26. Turn the ignition switch ON (II).





27. Check for continuity between EVAP canister vent shut valve 2P connector terminal No.2 and body ground with PCM connector terminal A4 jumped to body ground.

Is there continuity?

YES - Go to step 28.

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





28. 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 the O-ring (B).

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

Canister System Leak Test
29. Turn the ignition switch OFF.





30. 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 tee T-fittings and the vacuum pump to the other.





31. Remove the vent hose from the EVAP canister vent shut valve (A) and cap the port (B) to seal the fresh air vent for the EVAP canister.
32. Turn the ignition switch ON (II).





33. While monitoring FTP sensor voltage with the Honda PGM Tester, or measuring voltage between PCM connector terminals A29 and C18, slowly pump the vacuum pump.
34. Continue to pump vacuum until the voltage drops to about 1.5 V. Make sure your vacuum pump has no leak.
35. Check the voltage for 20 seconds.

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

YES - Check the EVAP canister vent shut valve line and connections for misrouting, poor connections, damage, or pinched areas.

NO - Go to step 36.

36. Turn the ignition switch OFF.





37. Disconnect the quick-connect fitting (A) from the EVAP canister, and plug the canister port (B).
38. Turn the ignition switch ON (II).





39. While monitoring FTP sensor voltage with the Honda PGM Tester, or measuring voltage between PCM connector terminals A29 and C18, slowly pump the vacuum pump.
40. Continue to pump vacuum until the voltage drops to about 1.5 V. Make sure your vacuum pump does not have a leak.
41. Monitor the voltage continuously for 20 seconds.

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

YES - Check the fuel tank vapor control line and connections for misrouting, poor connections, damage, or pinched areas. If the line and connections are OK, replace the fuel tank vapor control valve.

NO - Go to step 42.

42. Turn the ignition switch OFF.





43. Disconnect the purge line hose (A) from the canister at the metal line and plug the hose (B).
44. Turn the ignition switch ON (II).





45. While monitoring FTP sensor voltage with the Honda PGM Tester, or measuring voltage between PCM connector terminals A29 and C18, slowly pump the vacuum pump.
46. Continue to pump vacuum until the voltage drops to about 1.5 V. Make sure your vacuum pump does not have a leak.
47. Monitor the voltage continuously for 20 seconds.

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

YES - Check the EVAP canister purge valve line and connections for misrouting, poor connections, damage, or pinched areas. If the line and connections are OK, perform the EVAP two way valve test. If the line, the connections, and the EVAP two way valve are OK, replace the EVAP canister purge valve.

NO - Replace the EVAP canister.