P0456
DTC P0456 Evaporative Emission Control System Leak Detected (Very Small Leak)CIRCUIT DESCRIPTION
DTC Detecting Condition:
The vapor pressure sensor and the VSV for the canister closed valve (CCV) are used to detect abnormalities in the evaporative emission control system. The ECM decides whether there is an abnormality in the evaporative emission control system based on the vapor pressure sensor signal.
DTC P0442 or P0456 is recorded by the ECM when evaporative emissions leak from the components within the dotted line in Fig. 1, or when the vapor pressure sensor malfunctions.
HINT: Typical output of each trouble part.
Wiring Diagram:
Step 1 - 4:
Step 5 - 8:
Step 9 - 10:
Step 11 - 12:
INSPECTION PROCEDURE
HINT:
- if DTC P0441 (Purge Flow), P0446 (VSV for CCV) or P0451 (Evaporative Pressure Sensor) is output with DTC P0442 or P0456, first troubleshoot DTC P0441, P0446 or P0451. If no malfunction is detected, troubleshoot DTC P0442 or P0456 next.
- Ask the customer whether, after the MIL came on, the customer found the fuel tank cap loose and tightened it. Also ask the customer whether the fuel tank cap was loose when refuelling. If the fuel tank cap was loose, it was the cause of the DTC. If the fuel tank cap was not loose or if the customer was not sure if it was loose, troubleshoot according to the following procedure.
- Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
- When the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the vapor pressure sensor.
- EVAP LEAK TEST (with Hand-held tester)
This (EVAP LEAK TEST) confirm if there is a small leak (correspond to P0442) in the EVAP System.
a. Connect the hand-held tester to the DLC 3 connector of the vehicle.
b. Press "ON #" button on the hand-held tester.
c. Select the item "DIAGNOSIS/ENHANCED OBD II/SYSTEM CHECK/EVAP LEAK TEST" mode on the hand-held tester.
d. Perform "EVAP LEAK TEST".
e. If any changes do not occur within 1 minute after selecting "EVAP LEAK TEST", once remove the fuel tank cap, then set the fuel tank cap again.
Then perform "EVAP LEAK TEST".
If a leak is detected during this leak test, or if DTCs P0441, P0442 and P0446 are output simultaneously, conduct a leak test again after repair. If no leak found at this time, the EVAP system recovered normal.