Circuit Description

Evaporative (EVAP) system includes fuel tank, EVAP canister vent solenoid, fuel tank pressure sensor, fuel tank pressure control valves, EVAP tank pressure control solenoid vacuum valve, fuel lines and hoses, vapor and purge lines, fuel cap, EVAP canister, and EVAP canister purge solenoid valve. When EVAP canister purge solenoid valve and EVAP canister vent solenoid are turned on, engine vacuum is applied to entire EVAP system. PCM monitors amount of vacuum decay based on fuel tank pressure sensor input.

When DTC sets, MIL will illuminate after 2 consecutive ignition cycles in which diagnostic runs with active fault. PCM will record operating conditions at time of diagnostic failure and store information in FREEZE FRAME/FAILURE RECORDS data buffer.