Kia Optima Hybrid: Evaporative Emission Control System / NVLD(Natural Vacuum Leakage Detection) Description and Operation

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual / Emission Control System / Evaporative Emission Control System / NVLD(Natural Vacuum Leakage Detection) Description and Operation

Description

NVLD(Natural Vacuum Leakage Detection) is located between the canister and the fuel tank air filter. NVLD is to detect leaks equivalent to a 0.5 mm hole in the fuel tank, canister and hoses. When the engine has been running, the temperature of the fuel in the fuel tank is raised slightly. When the engine is shut off, the temperature of the fuel should drop. The ideal gas law states that in a sealed system the pressure drops proportionately to a drop in temperature.

[No leak]

[With 0.5mm leak]

While the engine is shut off, ECM monitors a pressure switch that is built into the NVLD for detecting slight drop in pressure. If the switch change is not detected after an engine shut down, it assumes there is a leak in the sealed system.

Fuel Tank Air Filter Repair procedures

Removal 1. Turn the ignition switch OFF and disconnect the battery negative (-) cable. 2. Lift the vehicle. 3. Disconnect the canister close valve connector (A). 4. Disconnect the ventilation hose (B) ...

NVLD(Natural Vacuum Leakage Detection) Specifications

Specification Pressure [kPa (kgf/cm?, in H2O)Output Voltage (V)-6.67 (-0.068, -26.8)0.502.5+6.67 (0.068, 26.8)4.5 ...

Other information:

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual: Valve Body Description and Operation

Description The valve body is essential to automatic transaxle control and consists of various valves used to control the oil feed from the oil pump. Specifically, these valves consist of pressure regulator valves, oil redirection valves, shift valves, and manual valves. The body also features electronic ...

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual: Positive Crankcase Ventilation (PCV) Valve Repair procedures

Removal 1. Disconnect the vapor hose (A). 2. Remove the PCV valve (B). Inspection 1. Insert a thin stick (A) into the PCV valve (B) from the threaded side to check that the plunger movement. If the plunger does not move (PCV valve is clogged), clean or replace the valve. Installation 1. ...