Repair Procedures: Inspection

When the engine is shut off, the pressure change in the fuel tank by the ambient temperature is monitored by NVLD and when the engine is started, ECM judges whether there is a leak or not through the monitored data.

If a leak is detected, ECM displays DTC P0455 or P0456.

Process overview 

If a leak is detected by NVLD, inspect the vehicle as the flow chart below to distinguish whether the error was caused by leakage of fuel system or NVLD itself.

Fig 1: NVLD Trouble Shooting Diagram

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Leakage Test with FTPS(Fuel Tank Pressure Sensor) 

If a leak is detected by NVLD, leakage test with FTPS is performed more than 3~5 times to check tank system components. This test is only for production line or service shop to check where the real cause(NVLD or fuel system) of DTC P0455 or P0456 is.

1. Turn the ignition switch OFF.
2. Connect the GDS to Data Link Connector (DLC).
3. Start the engine.
4. Select "Vehicle, Model year, Engine, System".
5. Select "Vehicle S/W Management".
6. Select "Inspection/Test".
7. Select "Evap. Leak Test"
8. Perform the test in accordance with the image below.
   Fig 2: Display - EVAP Leakage Setup Test Screen Using GDS

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   Fig 3: Display - EVAP Leakage Test Ok Screen

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   Fig 4: Display - EVAP Leakage Test Completion Screen

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