P0442: Evaporative Emission Control System Leak Detected (Small Leak)

written by Steven Ewing^{Director, Editorial Content
Steven Ewing has worked in the automotive industry since 2003. In that time, he's written thousands of articles and tested just as many vehicles. Steven is Edmunds' director of editorial content and has previously been on staff at Winding Road magazine, Autoblog, Motor1.com, CNET, and was the U.S. correspondent for Top Gear magazine. Steven has also contributed to Automobile magazine, Car and Driver, The Drive, Jalopnik, Porsche Panorama, and dozens of other publications. In his spare time, Steven loves to play the drums, cook, and drive his 1999 BMW M Roadster to local punk shows.}
10/25/2024
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The P0442 error code means your vehicle has detected a small leak in its evaporative emissions control, or EVAP, system. Because the EVAP system controls your vehicle's emissions, it's important to address even the smallest of problems. A leak can contribute to increased pollutants being distributed into the air. It can also reduce your vehicle's fuel efficiency.

Can I safely drive my car with the P0442 error code?

Yes, your vehicle is safe to drive with this error code displayed. But driving like this for a prolonged period of time can lead to increased emissions and potentially damage your EVAP system further. It's best to address the problem as soon as possible.

Common symptoms of a P0442 error code

Your vehicle's check engine light is on
You might smell fuel inside or near the vehicle
You could notice a small decrease in fuel efficiency
If your state requires emissions testing, this code would cause your vehicle to fail

How to diagnose the P0442 error code

This code is found via an OBD-II scanner, which detects trouble codes inside your vehicle's onboard computer. A trained mechanic may also inspect the EVAP components — things like hoses or even the fuel cap — for signs of damage.

To determine if there's a leak, a mechanic may blow smoke into the vehicle's EVAP system. The mechanic can then detect the source of the leak if smoke appears in the circuit. Specific parts of the EVAP system — the purge valve, vent valve, etc. — may also be tested to ensure they're working properly.

Repairing the P0442 error code

One or more of the following steps may be involved in repairing your vehicle's EVAP system.

Replacing the fuel cap
Repairing or replacing damaged hoses
Replacing any of the aforementioned components (purge valve, vent valve, etc.)
Clearing the code from the vehicle's onboard computer

Related reading

Follow the link below to reach our diagnostic check engine trouble codes catalog:
On-board diagnostics (OBD-II) trouble code directory

by Steven Ewing

Steven Ewing has worked in the automotive industry since 2003. In that time, he's written thousands of articles and tested just as many vehicles. Steven is Edmunds' director of editorial content and has previously been on staff at Winding Road magazine, Autoblog, Motor1.com, CNET, and was the U.S. correspondent for Top Gear magazine. Steven has also contributed to Automobile magazine, Car and Driver, The Drive, Jalopnik, Porsche Panorama, and dozens of other publications. In his spare time, Steven loves to play the drums, cook, and drive his 1999 BMW M Roadster to local punk shows.

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