Circuit Description

EVAP purge valve allows fresh outside air to enter the canister during purge modes. The vent solenoid is closed only while EVAP diagnostic runs. Voltage on solenoid control circuit is monitored continuously. DTC will set when voltage remains above an upper threshold.

DTC will set when:

• Battery voltage between 7.5-15.0 volts.
• Engine speed greater than 40 RPM.
• A low voltage condition exists in control circuit.

When DTC sets, MIL will illuminate after 2 consecutive ignition cycles in which diagnostic runs with active fault. ECM will record operating conditions at time of diagnostic failure and store information in freeze frame buffer.