P0449Powertrain
Powertrain · SAE
EVAP Vent Solenoid Valve — Circuit Fault
Meaning
The ECU detects an electrical anomaly (open circuit, short circuit, or out-of-range signal) in the circuit of the EVAP canister vent solenoid (identified as N115 in some OEM nomenclatures). The EVAP system cannot correctly control fuel tank pressure.
Common causes
- Broken or shorted EVAP vent solenoid wiring
- Corroded or disconnected solenoid connector
- Internally open or shorted solenoid coil
- Damaged ECU driver for the vent solenoid
- Blown fuse or failed relay in the solenoid supply circuit
Symptoms
- Malfunction indicator lamp (MIL) on
- EVAP system inoperative: tank pressure uncontrolled
- EVAP leak detection monitor failure
- Possible fuel vapor odor
- Generally no driveability symptoms
Severity
Moderate: the evaporative emission control system is disabled; the vehicle will not pass OBD/emissions tests until the fault is resolved.
What to do
- Measure vent solenoid coil resistance at the connector (typically 22–32 Ω; open or shorted reading indicates a replacement)
- Verify supply voltage at the solenoid connector with ignition on
- Check the ECU command signal (PWM) at the solenoid
- Inspect wiring for breaks, shorts to ground, or shorts to power
- Replace the EVAP vent solenoid or repair the wiring based on findings