Mode B:

Introduce the negative pressure in the intake manifold to the tank.

Approx. 0 --> -1.4 kPa (0 --> -10.5 mmHg, 0 --> -0.41 inHg) (0.04-in diagnosis)

Approx. 0 -->-3.05 kPa (0 --> -22.9 mmHg, 0 --> -0.9 inHg) (0.02-in diagnosis)

When the pressure above (desired negative pressure) is reached, Mode C is entered.

In this case, if the tank pressure does not become the desired negative pressure, judge that there is a large leakage in the system.

Judge NG when the malfunction criteria below is completed.

Finish the Evap. diagnosis when judging large leak (35 seconds) in 0.04-inch diagnosis. Cancel the diagnosis (62 seconds) in 0.02-inch diagnosis.