DTC Troubleshooting
DTC Troubleshooting: P0455, P0456
DTC P0455: EVAP System Large Leak Detected
DTC P0456: EVAP System Very Small Leak Detected
NOTICE
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, Snap-on YA4000A or equivalent, commercially available
- Vacuum/pressure gauge, 0-4 in.Hg 07JAZ-001000B
NOTE:
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Reading and Clearing Diagnostic Trouble Codes
- Fresh fuel has a higher volatility that will create greater pressure/vacuum. The best condition for testing is less than a full tank of fresh fuel. 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.
1. Check the fuel fill cap (the cap must say TIGHTEN TO CLICK). It should turn 1/4 turn after it's tight, then it clicks.
Is the correct fuel fill cap installed and properly tightened?
YES - Go to step 2.
NO - Replace or tighten the cap, then go to step 29.
2. Check the fuel fill cap seal (A) and the fuel fill pipe mating surface (B). Verify that the fuel fill cap tether cord (C) is not caught under the cap.
Is the fuel fill cap seal missing or damaged, is the fuel fill pipe damaged, or is the tether cord caught under the cap?
YES - Replace the fuel fill cap or the fuel fill pipe, then go to step 29.
NO - Go to step 3.
3. Turn the ignition switch to ON (II).
4. Clear the DTC with the HDS.
5. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, the EVAP canister vent shut valve, and the PCM.
NO - Go to step 6.
6. Turn the ignition switch to LOCK (0).
7. Check for a poor connection or damage at the fuel tank vapor recirculation tube.
Is the tube OK?
YES - Go to step 8.
NO -
- Replace the fuel tank vapor recirculation tube, then go to step 29.
- If needed, replace the fuel tank, Service and Repair then go to step 29.
8. Remove the trunk floor trim panel.
9. Remove the EVAP access panel from the floor.
10. Disconnect the fuel tank vapor recirculation tube (A) and the fresh air hose (B) from the EVAP canister (C), and plug the EVAP canister port (D).
11. Disconnect the vacuum hose (engine side) (A) from the EVAP canister purge valve (B) in the engine compartment, and connect a T-fitting (C) from the vacuum gauge and the vacuum pump/gauge, 0-30 in.Hg, to the hose as shown.
12. Turn the ignition switch to ON (II).
13. Select EVAP PCS ON in the INSPECTION MENU with the HDS.
14. Apply vacuum to the hose until the FTP reads 1.90 V (0.59 in.Hg, -15.1 mmHg).
NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.
15. Select EVAP PCS OFF in the INSPECTION MENU with the HDS, then disconnect the vacuum pump/gauge.
16. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS.
Does the voltage increase more than 0.2 V (0.1 in.Hg, 0.5 mmHg)?
YES - Go to step 17.
NO - Go to step 22.
17. Reconnect the vacuum hose (engine side) to the EVAP canister purge valve.
18. Disconnect the vacuum hose (EVAP canister side) from EVAP canister purge valve (A) in the engine compartment, and connect a T-fitting (B) from the vacuum gauge and the vacuum pump/gauge to the hose as shown.
19. Apply vacuum to the hose until the FTP reads 1.90 V (-0.59 in.Hg, -15.1 mmHg).
NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.
20. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS.
Does the voltage increase more than 0.2 V (0.1 in.Hg, 0.5 mmHg)?
YES - Go to step 21.
NO - Replace the EVAP canister purge valve, Service and Repair then go to step 30.
21. Check for a loose or damaged EVAP canister purge line between the EVAP canister and the EVAP canister purge valve, or a leaking EVAP canister purge valve.
Are the line and the EVAP canister purge valve OK?
YES - Replace these parts, then go to step 30:
- FTP sensor O-ring
- EVAP canister vent shut valve case and O-ring
- EVAP canister
NO - Reconnect or repair the EVAP canister purge hose, then go to step 30.
22. Reconnect the fresh air hose (A).
23. Reconnect the vacuum hose (engine side) to the EVAP canister purge valve.
24. Disconnect the vacuum hose (EVAP canister side) from EVAP canister purge valve (A) in the engine compartment, and connect a T-fitting (B) from the vacuum gauge and the vacuum pump/gauge to the hose as shown.
25. Select the CVS ON in the INSPECTION MENU with the HDS.
26. Apply vacuum to the fuel tank vapor recirculation tube (disconnected in step 10) until the FTP reads 1.90 V (-0.59 in.Hg, -15.1 mmHg).
NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.
27. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS.
Does the voltage increase more than 0.2 V (0.1 in.Hg, 2.5 mmHg)?
YES - Replace the EVAP canister vent shut valve, then go to step 30.
NO - Go to step 28.
28. Select EVAP CVS OFF in the INSPECTION MENU with the HDS.
29. Check these parts for looseness or damage:
- Fuel fill pipe
- Fuel vapor return pipe
Are the parts OK?
YES - Check the fuel tank unit base gasket Fuel Tank Unit Removal/Installation and the fuel tank, then go to step 30.
NO - Repair or replace the damaged part(s), then go to step 30.
30. Reconnect all hoses and connectors.
31. Turn the ignition switch to ON (II).
32. Reset the PCM with the HDS.
33. Do the PCM idle learn procedure. PCM Idle Learn Procedure
34. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES - Go to step 35.
NO - Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, the EVAP canister vent shut valve, and the PCM, then go to step 1.
35. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0455 and/or P0456 indicated?
YES - Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, the EVAP canister vent shut valve, and the PCM, then go to step 1.
NO - Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.