P1421 – EVAP System Cold Start Fault (Ford)

Description

P1421 Ford indicates incorrect EVAP purge flow detected during cold start conditions.

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Symptoms

  • Rough idle
  • Hard starting
  • Fuel smell

Causes

  • Faulty purge valve
  • Stuck vent valve
  • Vacuum leak

Diagnosis

  • Check purge flow
  • Inspect vent valve
  • Smoke test EVAP

Repair

  • Replace purge valve
  • Repair vacuum leaks
  • Replace vent valve

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