P0456
DTC P0455 or P0456
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0455
- Evaporative Emission (EVAP) System Large Leak Detected
DTC P0456
- Evaporative Emission (EVAP) System Very Small Leak Detected
Circuit/System Description
The diagnostic strategy for the EVAP system uses a vacuum pump to test for system leaks after the engine is OFF. A unique fuel tank, EVAP canister, and EVAP vacuum leak pump, work together in order to provide enhanced system diagnosis. The vacuum leak pump, the fuel tank pressure (FTP) sensor and the EVAP canister vent valve are all integral parts of one assembly. The assembly is attached directly to the EVAP canister, located near the fuel tank.
After the vehicle has sat with the engine OFF for greater than 5 hours and the engine coolant temperature is less than 35°C (95°F), a comprehensive diagnostic is enabled. The complete diagnostic test can take up to 15 minutes to run, with leak detection comprising the largest portion of the test. The DTC P0455 diagnostic detects evaporative emission system leaks as small as 1.0 mm (0.040 in) and the P0456 diagnostic detects leaks as small as 0.51 mm (0.020 in).
Conditions for Running the DTC
* DTCs P0011, P0012, P0100, P0101, P0102, P0103, P0110, P0112, P0113, P0115, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0220, P0222, P0223, P0300-P0304, P0335, P0339, P0340, P0341, P0351-P0354, P043E, P043F, P0441, P0443, P0450, P0451, P0452, P0453, P0500, P2135, P2401, P2402, P2419, P2420, P2610 are not set.
* Intake air temperature is between 4-35°C (40-95°F).
* Atmospheric pressure is between 70-110 kPa.
* Five hours have elapsed after the engine was turned OFF.
* Battery voltage is greater than 10.5 volts.
* Engine coolant temperature is between 4-35°C (40-95°F).
* The ignition remains OFF for the duration of the test.
* DTC P0455 and P0456 run once per drive cycle when the above conditions are met.
Conditions for Setting the DTC
P0455
The specified minimum value of vacuum pressure was not obtained.
P0456
The specified minimum value of vacuum pressure cannot be maintained for the specified minimum length of time.
Action Taken When the DTC Sets
DTC P0455 and P0456 are Type B DTCs.
Conditions for Clearing the DTC
DTC P0455 and P0456 are Type B DTCs.
Diagnostic Aids
* When testing for a leak you must use a plug in the EVAP air filter inlet hose to properly seal the EVAP system. This EVAP system cannot be sealed with a scan tool. Failure to properly seal the system will cause a false leak indication when leak testing, and may also allow smoke to exit the fresh air inlet that is located near the filler cap.
* In order to improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
* Testing the EVAP system from the purge solenoid valve purge line allows the fuel filler cap to be left in place so that the fuel cap to fuel filler neck seal can be tested for leaks.
Reference Information
Schematic Reference
Evaporative Emissions Hose Routing Diagram ([1][2]Diagrams)
Description and Operation
Evaporative Emission Control System Description (Evaporative Emission Control System Description)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
* J 41413-SPT High Intensity White Light
* J 41413-200 Evaporative Emissions System Tester (EEST)
* J 41413-300 EVAP Cap and Plug Kit
* J 41413-311 EVAP Plug
Circuit/System Verification
1. Verify the EVAP system using the EVAP Service Bay Test, refer to Service Bay Test (Service Bay Test).
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0441 is not set.
If the DTC is set, refer to DTC P0441 (P0441).
Note:
* The fresh air intake to the EVAP system must be physically sealed to completely seal the EVAP system. This EVAP system cannot be completely sealed using a scan tool.
* Refer to J 41413-200 EEST operation manual for detailed instructions on how to use the Evaporative Emission System Tester to test for a leak and then locate the leak using smoke in Evaporative Emission System Diagnosis (Evaporative Emission System Diagnosis).
* Ensure that the underbody temperature of the vehicle and the tester are similar.
1. Raise the vehicle and disconnect the EVAP filter inlet hose at the quick connect fitting and plug the inlet to the filter with a J-41413-323 or J-41413-324 .
2. Lower the vehicle and connect the J 41413-200 EEST to the purge line on the EVAP canister side of the EVAP purge solenoid valve using the J 41413-311 emission plug brass cone adapter.
3. Use the J 41413-200 EEST to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes. It may take several minutes for the float to stabilize.
4. Use the flow meter on J 41413-200 , calibrated to 0.51 mm (0.020 in), to determine that there is no leak in the evaporative emission system.
• If a leak is detected, use the J 41413-200 EEST to apply smoke to the EVAP system at the purge tube until the leak is located using the J 41413-SPT white light.
Component Testing
Note: This test verifies the function of the FTP sensor. An inaccurate FTP sensor signal can set an EVAP system leak DTC.
1. Ignition ON, remove the fuel cap from the fuel tank filler neck. Observe that the FTP sensor scan tool parameter is 3.5-3.8 V.
• If the FTP sensor reading is not within the specified range, refer to DTC P0451 (P0451).
2. Test the operation of the EVAP canister and EVAP vacuum leak pump assembly. Refer to Evaporative Emission Control System Diagnosis (Evaporative Emission Control System Diagnosis).
• If a condition is found replace the affected component.
Repair Instructions
* Evaporative Emission Canister Filter Replacement (Service and Repair)
* Fuel Tank Replacement (Service and Repair)
* Evaporative Emission Canister Replacement (Service and Repair)
* Evaporative Emission Canister Purge Solenoid Valve Replacement (Service and Repair)
* Evaporative Emission System Vacuum Leak Pump Replacement (Service and Repair)
Repair Verification
1. Seal the system and use the flow meter on the EEST calibrated to 0.51 mm (0.020 in) to determine that there are no leaks in the EVAP system.
2. Remove any plugs or caps and reconnect the EVAP air filter inlet hose.
3. Clear DTCs