Circuit Description

EVAP purge valve serves to deliver fuel vapor from canister to intake manifold. Purge solenoid is Pulse Width Modulated (PWM) when ECM commands it to empty canister. Voltage on solenoid control circuit is monitored continuously. DTC will set when ECM does not detect any signal on the control circuit.

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.