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

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual / Engine Control/Fuel System / Engine 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.

CVVT Oil Control Valve (OCV) Repair procedures

Inspection 1. Turn the ignition switch OFF. 2. Disconnect the OCV connector. 3. Measure resistance between the OCV terminals 1 and 2. 4. Check that the resistance is within the specification. Specification: ...

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: Manifold Absolute Pressure Sensor (MAPS) Description and Operation

Description Manifold Absolute Pressure Sensor (MAPS) is a speed-density type sensor and is installed on the surge tank. It senses absolute pressure of the surge tank and transfers the analog signal proportional to the pressure to the ECM. By using this signal, the ECM calculates the intake air quantity ...

Kia Optima Hybrid (TF HEV) 2016-2020 Service Manual: Repair procedures

Fuel Pressure Test 1. Release the residual pressure in fuel line (Refer to “Release Residual Pressure in Fuel Line” in this group). When removing the fuel pump relay, a Diagnostic Trouble Code (DTC) may occur. Delete the code with the GDS after completion of “Release Residual Pressure ...