Circuit Description

PCM controls EVAP canister vent solenoid valve through ground circuit. If PCM commands vent solenoid on but voltage remains at 12 volts, or if PCM commands vent solenoid off but voltage remains at zero volts, DTC P0449 will set.

Conditions required to set DTC are:

• Ignition voltage is greater than 10 volts.
• Engine run time is greater than 32 seconds.

  The previous mentioned conditions and met, and one of the following conditions are met for 25 seconds within a 50 second period:

• PCM senses voltage is HIGH with EVAP canister vent solenoid commanded ON.
• PCM senses voltage is LOW with EVAP canister vent solenoid commanded OFF.