Vent Valve Symptoms: How It Fails and What You Notice
Key Takeaway
The vent valve is a common EVAP failure point. Here's how it fails and what you'll notice.
What Does the Vent Valve Do?
The vent valve allows fresh air into the charcoal canister during purge cycles and seals the system during leak tests. When it fails (stuck open or closed), EVAP codes trigger.
Failure Modes
| Failure | Resulting Code | Symptom |
|---|---|---|
| Stuck open | P0455, P0456 | Fails EVAP leak test |
| Stuck closed | P0446 | Tank pressure builds up |
| Intermittent | P0442, P0455 | Code comes and goes |
Symptoms
Replacement Cost
| Item | Cost |
|---|---|
| Vent valve (part) | $30 – $80 |
| Labor | $50 – $100 |
| Total | $80 – $180 |
ProHow Steer Helps
Steer identifies vent valve-related codes and distinguishes them from purge valve or gas cap issues.
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