P0456

DTC P0455 EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECTED (GROSS LEAK)
DTC P0456 EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECTED (VERY SMALL LEAK)

Malfunction Detection Condition:

DTC SUMMARY

DESCRIPTION
















While the engine is running, if a predetermined condition (closed-loop, etc.) is met, the purge VSV is opened by the ECM and stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the duty cycle ratio of the purge VSV to control purge flow volume.

The purge flow volume is also determined by the intake manifold pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that the purge flow is maintained when the negative pressure (vacuum) is applied to the canister.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Enabling Conditions (Part 2):

Typical Malfunction Thresholds:

5 hours* after the ignition switch is turned OFF, the leak detection pump creates negative pressure (vacuum) in the EVAP system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

HINT: *:If the engine coolant temperature is not below 35 degrees C (95 degrees F) 5 hours after the ignition switch is turned OFF, the monitor check starts 2 hours later. If it is still not below 35 degrees C (95 degrees F) 7 hours after the ignition switch is turned OFF, the monitor check starts 2.5 hours later.







1. P0455: EVAP gross leak
In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than [second 0.02 inch leak criterion x 0.2] (near atmospheric pressure), the ECM determines that the EVAP system has a large leakage, illuminates the MIL and sets the DTC (2 trip detection logic).




2. P0456: EVAP very small leak
In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than the second 0.02 inch leak criterion, the ECM determines that the EVAP system has a small leakage, illuminates the MIL and sets the DTC (2 trip detection logic).

MONITOR RESULT
Refer to CHECKING MONITOR STATUS. Checking Monitor Status

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INSPECTION PROCEDURE

NOTE: The hand-held tester is required to conduct the diagnostic troubleshooting procedure.

HINT:
- Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.