P2421 low

EVAP Vent Valve Stuck Open

The P2421 code means the vehicle's onboard diagnostic system has detected: EVAP Vent Valve Stuck Open. This is a low severity code.

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Keep driving?
Yes, but fix soon
DIY difficulty
moderate
Estimated cost
$75 - $350 (parts and labor)
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Common Symptoms

  • Check Engine Light illuminated
  • Failed emissions inspection
  • Fuel vapor smell near rear of vehicle
  • No noticeable performance issues
  • EVAP system leak codes may also be present

Probable Causes (Ranked by Likelihood)

  • EVAP vent valve stuck in the open position Very High
  • Carbon or debris blocking vent valve from closing High
  • Failed vent valve solenoid Moderate
  • Wiring issue preventing vent valve from closing Low

Step-by-Step Diagnostic Procedure

  1. Command the vent valve closed with a scan tool and listen for activation

  2. Check the vent valve for debris blocking the valve mechanism

  3. Measure vent valve solenoid resistance

  4. Inspect wiring and connector at the vent valve

  5. Perform EVAP smoke test with vent valve commanded closed

Frequently Asked Questions

Can I drive with code P2421?

Yes, safe to drive. The stuck vent valve prevents proper EVAP system testing but does not affect driving performance.

What causes P2421?

Usually the vent valve is stuck open from debris or a failed solenoid. The valve is typically located near the charcoal canister at the rear of the vehicle.

Is P2421 expensive to fix?

Typically $75 to $350. The vent valve is an inexpensive part. Accessing it near the fuel tank may add some labor cost.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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