Code
P0447
GWM
P — Powertrain
- The ventilation circuit for the fuel vapor outlet control system is open
Views:
UK: 19
EN: 24
RU: 28
AI status
Completed
Completed
100%
Causes
- Open or high-resistance wiring in vent control circuit
- Faulty EVAP vent/ventilation control valve (vent solenoid)
- Poor or corroded connector or pin(s)
- Blown fuse or faulty relay powering the EVAP circuit
- PCM driver fault (rare) or poor PCM ground
- Aftermarket radio/alarms or repairs that disturbed wiring
Symptoms
- Check Engine Light / MIL illuminated
- Stored P0447 trouble code (may be accompanied by other EVAP codes)
- Possible failed EVAP system leak tests / readiness incomplete
- No noticeable drivability problems in many cases
What to check
- Retrieve freeze-frame and other stored EVAP codes with a scan tool
- Visually inspect EVAP vent valve, harness, and connector for damage, corrosion, or disconnection
- Check related fuses and any EVAP relays
- Use a scan tool to command the vent valve ON/OFF and observe response
- Measure coil resistance of the vent valve and compare to specification
- Perform backprobe voltage and ground checks at the vent valve connector while commanding
Signal parameters
- Vent solenoid coil resistance: typically ~10–50 ohms (check vehicle-specific spec)
- Controlled by PCM: expect switched battery voltage (~12 V) or ground on the control pin when commanded
- At rest (not commanded) control wire may be at battery voltage or near 0 V depending on vehicle design
- When commanded ON, voltage at control pin should change (0 V to ~12 V or pulsed/PWM). Use a lab scope or multimeter to confirm switching
- No continuity (open) on the control circuit indicates wiring or solenoid open
Diagnostic algorithm
- Connect a scan tool, confirm P0447 and check for other EVAP codes (P0446, P0443, P0441, etc.). Record conditions that set the code.
- Visually inspect the EVAP vent valve, nearby hoses, and the electrical connector for damage, pushed-out pins, or corrosion. Repair any obvious issues.
- Check EVAP-related fuses and relays. Replace if blown or faulty, then clear code and retest.
- Backprobe the vent valve connector. With harness connected, command the valve ON/OFF with the scan tool and observe control pin voltage and ground. Compare to expected behavior.
- With harness disconnected, measure vent valve coil resistance with a multimeter. If open or far outside spec, replace the valve.
- If coil resistance is normal but no command voltage at the connector when commanded, check continuity between the connector and the PCM control pin. Repair open or shorted wiring as needed.
- Check grounds: verify good chassis/PCM ground paths related to the EVAP circuit.
- If wiring and valve check good but circuit still shows open, bench-test or swap with known-good valve (if available) to isolate PCM vs valve. Do not attempt PCM repair without further diagnosis.
- After repairs, clear codes, cycle ignition, and perform readiness/EVAP tests or a road drive. Verify code does not return and EVAP monitors complete.
Likely causes
- Disconnected or damaged harness at the EVAP vent valve
- Failed vent control solenoid (open coil or internal break)
- Corroded terminal(s) at the valve connector
- Open fuse or wiring between fuse and valve
- Open or broken ground or open control output from PCM
Fault status
Status
P0447 indicates an open circuit or lack of expected signal in the EVAP vent/ventilation control circuit. The PCM set the code when it detected no/abnormal control feedback; the MIL may be illuminated and EVAP monitor may not complete.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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