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Code

P0440

Evaporative emissions

EVAP system malfunction

The evaporative system has a malfunction.

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Most likely causes

Loose fuel cap
EVAP leak
Faulty purge valve

Symptoms you may notice

Check engine light

Checks to run

Tighten the fuel cap
Smoke test
Test the purge valve

Tools you may need

Smoke machine

Always diagnose before replacing. Codes share symptoms; confirm the cause with measurements before buying parts.

Related codes in Evaporative emissions

Small leak in EVAP system

EVAP vent valve control circuit malfunction

Large leak in EVAP system

Very small leak in EVAP system

EVAP pressure sensor high input

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