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P0442 Category: Powertrain
Urgency: Moderate Severity

P0442: EVAP System Leak Detected (Small Leak)

Code P0442 indicates that the evaporative emission control (EVAP) system detected a small vapor leak (typically 0.020 to 0.040 inches) in fuel vapor lines.

Common Symptoms of P0442

  • Check Engine Light on
  • Faint gasoline vapor smell near fuel tank
  • No noticeable loss in driving performance

Root Causes for Code P0442

  • Loose, worn, or cracked fuel filler gas cap
  • Cracked or disconnected EVAP vapor hose
  • Faulty EVAP canister purge valve or vent solenoid
  • Cracked charcoal vapor canister

Step-by-Step DIY Diagnostic & Inspection Guide

1

Remove, inspect rubber O-ring seal, and retighten gas cap until it clicks.

2

Inspect EVAP solenoid valves for debris and test with 12V power.

3

Perform an EVAP low-pressure smoke test.

Estimated Repair Costs

Replacement Parts: $15 - $120
Shop Diagnostic / Labor: $50 - $150
Total Estimated Cost: $65 - $270

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