Circuit Description

For circuit description, see Fig 1. Detecting condition of DTC P0450 is when 10 seconds or less after the engine starts, the following conditions continue for 7 seconds or more (2 trip detection logic):

• Vapor pressure sensor value is less than -4.0 kPa (-30 mmHg, -1.2 in.Hg).
• Vapor pressure sensor value is greater than or equal to 2.0 kPa (15 mmHg, 0.6 in.Hg).

Detecting condition of DTC P0451 is when the vapor pressure sensor output extremely changes under the following conditions (2 trip detection logic):

• Vehicle speed is 0 mph (0 km/h) and engine speed is idling and vacuum switching valve (VSV) for pressure switching valve is OFF.
• Vapor pressure sensor value is greater than or equal to opening pressure valve of charcoal canister.