Is It Safe to Drive With a P0442 Code?

Generally Safe to Drive — But Get It Checked
This fault is unlikely to cause immediate danger or breakdown, but it will cause an MOT failure and should be diagnosed and cleared before your next test.

Common Symptoms of a P0442 Fault

EML on
Possible faint fuel smell
No driveability symptoms

Possible Causes of P0442

A P0442 code can be triggered by faults in several different vehicle systems. Identifying the specific root cause requires proper diagnostic equipment and live data analysis — not just reading the code itself.

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Fuel Cap Seal Issue
Fuel cap O-ring worn or cap not fully tightened — check first.
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EVAP Hose Small Crack
A hairline crack in an EVAP hose or pipe.
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Purge or Vent Valve Sealing Issue
A valve not sealing correctly allowing a small leak.
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Charcoal Canister Micro-Crack
Small crack in the charcoal canister body.
Why we don't list the exact part: A P0442 code tells you what's happening but not why. Replacing parts based on the code alone without proper diagnosis is the most common way drivers waste money. A proper diagnosis identifies the exact cause first.
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P0442 and Your MOT

A stored P0442 fault code will cause your car to fail its MOT. The engine management light will be illuminated during the test, which is an automatic failure under current MOT testing standards. Even if the light clears temporarily, the code remains in the ECU memory and can be read by the tester's equipment.

Get the fault properly diagnosed and repaired first — then have the code cleared and confirm the light doesn't return before booking your test.

Related Fault Codes

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