P0442 on a Nissan

What is different about P0442 on a Nissan?

The same salt-belt corrosion pattern documented for Nissan's vent control valve can produce a range of leak sizes depending on how far the corrosion has progressed.

What Nissan owners run into with P0442

Partial vent control valve corrosion: A vent control valve that is only partially corroded, rather than fully compromised, is documented to produce a medium-sized leak effect on some Nissan models, resulting in P0442 rather than the larger leak code.

Gas cap seal wear at an intermediate stage: As with most makes, a gas cap seal worn enough to leak more than a minor amount but less than a severe amount is a documented cause of P0442 specifically.

What to check first on a Nissan

The order below narrows the generic P0442 list down to what is worth checking first on this make. It is a starting order, not a diagnosis: patterns are generation specific and a vehicle outside those generations may have none of them.

Check in this order

• Check the gas cap seal for wear
• Inspect the EVAP vent control valve for partial corrosion, especially in regions with heavy winter road salt use
• Inspect EVAP hoses for a leak of intermediate size
• Use a smoke test if available to help pinpoint the leak

The generic picture behind P0442

The computer periodically seals the evaporative system and watches for a pressure or vacuum change over time to test for leaks. This code sets when that test finds a leak small enough to fall into the mid-size category the manufacturer defines, larger than the smallest detectable leak but smaller than an obvious opening such as a loose cap.

Everything on the main P0442 page still applies here. This page narrows the cause list to the patterns documented on Nissan vehicles, it does not replace the underlying definition.

The generic version of this code

• P0442 on any vehicle