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 system 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 ECM/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 higher volatility that will create greater pressure/vacuum. The optimum condition for testing is fresh fuel, and there must be less than a full tank of fuel. If possible, to assist in leak detection, add one 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 the vacuum pump to the hose.




2. Turn the EVAP canister purge valve on with the Honda PGM Tester, then connect ECM/PCM connector terminal A6 to body ground with a jumper wire.
3. Turn the ignition switch ON (II).
4. Apply vacuum to the hose.

Does the valve hold vacuum?

YES - Go to step 5.

NO - The EVAP canister purge valve is OK. Go to step 10.

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




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

Is there continuity?

YES - Go to step 8.

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

8. Turn the ignition switch ON (II).




9. 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 (ECM/PCM) CRUISE CONTROL (15 A) fuse.

EVAP Bypass Solenoid Valve Test




10. Disconnect the vacuum hose from the EVAP two- way valve (A), and connect a vacuum pump to the hose.
11. Turn the ignition switch ON (II).
12. 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 18.

NO - Go to step 13.

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







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

Is there continuity?

YES - Go to step 16.

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

16. Disconnect ECM/PCM connector A (32P).




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

Is there continuity?

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

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

EVAP Canister Vent Shut Valve Test




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




19. With the Honda PGM Tester in the EVAP test mode, turn on the bypass solenoid, or connect ECM/PCM connector terminal A4 to body ground with a jumper wire.
20. Turn the ignition switch ON (II)
21. Apply vacuum to the hose.

Does the valve hold vacuum?

YES - The EVAP canister vent shut valve is OK. Go to step 27.

NO - Go to step 22.

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




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

Is there continuity?

YES - Go to step 25.

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

25. Turn the ignition switch ON (II).




26. 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 (ECM/PCM) CRUISE CONTROL (15 A) fuse.

Canister System Leak Test

27. Turn the ignition switch OFF.




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




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




31. While monitoring the Fuel Tank Pressure sensor voltage with the Honda PGM Tester, or measuring voltage between ECM/PCM connector terminals A 29 and C18, slowly pump the vacuum pump.
32. Continue to pump until the voltage drops to about 1.5 V. Make sure your vacuum pump has no leak.
33. Monitor the voltage for 20 seconds.

Does the voltage drop to about 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 34.

34. Turn the ignition switch OFF.




35. Disconnect the quick-connect fitting (A) from the EVAP canister, and cap the canister port (B).
36. Turn the ignition switch ON (II).




37. While monitoring FTP sensor voltage with the Honda PGM Tester, or measuring voltage between ECM/PCM connector terminals A29 and C18, slowly pump the vacuum pump.
38. Continue to pump vacuum until the voltage drops to about 1.5 V.
39. Check the voltage for 20 seconds.

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

YES - Inspect the fuel tank vapor line and connections for vacuum leaks.

NO - Go to step 40.

40. Turn the ignition switch OFF.




41. Disconnect the purge line hose (A) from the canister at the metal line and cap the canister port (B).
42. Turn the ignition switch ON (II).




43. While monitoring FTP sensor voltage with the Honda PGM Tester, or measuring voltage between ECM/PCM connector terminals A29 and C18, slowly pump the vacuum pump.
44. Continue to pump 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.
45. Monitor the voltage for 20 seconds.

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

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

NO - Replace the EVAP canister.