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P0446 on a 2017 Honda Civic

EVAP Vent Control Circuit Fault

P0446 on a 2017 Honda Civic indicates evap vent control circuit fault. It usually stays drivable short-term but should be diagnosed promptly. The most common cause is failed evap vent valve / vent solenoid (mechanical sticking) (typically $80–$350). Confirm the root cause before replacing parts.

Severity: low Safe to drive (short term) Compact Sedan 2015-2019 Honda Civic

Reviewed by MECH AI Editorial · Last verified · Includes 20 active NHTSA TSBs

What does P0446 mean on a 2017 Honda Civic?

P0446 is set when the engine control module detects that the EVAP vent valve circuit is not behaving as commanded. The vent valve is the normally-open solenoid that lets the charcoal canister breathe — and closes during the EVAP leak test to seal the system. P0446 typically means the vent valve is stuck (mechanically or electrically) so that the system can never seal properly for the leak test.

This guide covers P0446 across the 2015-2019 Honda Civic generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2015 through 2019.

Is it safe to drive a 2017 Honda Civic with P0446?

In most cases a 2017 Honda Civic stays drivable for short trips with P0446 active, but diagnose and repair it promptly. This is a low-severity code — ignoring it can lead to further damage or a failed emissions test.

What are the symptoms of P0446 on a 2017 Honda Civic?

What causes P0446 on a 2017 Honda Civic?

Cause Likelihood Estimated repair (USD)
Failed EVAP vent valve / vent solenoid (mechanical sticking) Most common $80–$350
Dirt, debris, or spider webs clogging the vent valve filter Common on trucks and SUVs with the canister mounted under the vehicle. Common $20–$100
Damaged wiring or connector at the vent valve Common $50–$250
Failed PCM driver circuit for the vent valve (rare) Rare $400–$1,500
Cracked or saturated EVAP charcoal canister Occasional $200–$600

How to diagnose this on a 2017 Honda Civic

  1. Locate the vent valve on this vehicle

    The vent valve is mounted on or next to the charcoal canister. On most modern trucks and SUVs that is behind the rear bumper or near the fuel tank. On many cars it sits in the engine compartment. Consult the service manual for the exact location.

    Tools: Vehicle-specific service information

  2. Test the vent valve electrically

    Disconnect the valve connector. With the key on, check for battery voltage on the power side. Apply 12 V across the solenoid terminals directly — you should hear and feel it click. A solenoid that does not click is dead and needs replacement.

    Tools: Multimeter, Test leads / jumper wires

  3. Test the vent valve mechanically

    Disconnect the hose at the vent valve. Connect a hand vacuum pump. With the solenoid de-energized, the valve should let air flow freely (no vacuum holds). With 12 V applied, the valve should hold vacuum. A valve that holds vacuum at rest, or that leaks vacuum when commanded closed, is the problem.

    Tools: Hand vacuum pump, 12 V test source

  4. Inspect for contamination

    Trucks and SUVs frequently get spider webs, mud, or sand inside the vent valve filter on the canister side. Some vehicles have a dust filter that is replaceable; others integrate it into the valve assembly. Clean or replace as needed.

    Tools: Compressed air, Replacement filter (if applicable)

  5. Confirm the canister itself is intact

    With the vent valve removed, look into the canister port for cracked plastic, saturated charcoal (will smell strongly of fuel), or debris. A failed canister will cause repeated P0446 set events even after the vent valve is replaced.

    Tools: Flashlight

Known Technical Service Bulletins for the 2015-2019 Honda Civic

Manufacturers publish Technical Service Bulletins (TSBs) when a known issue affects a specific vehicle. These bulletins come from the NHTSA database for your Honda Civic.

+14 more TSBs available in MECH AI's TSB explorer for this vehicle.

NHTSA complaints & recalls for the 2017 Honda Civic

Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2017 Honda Civic. Use these to gauge how common a problem is on your specific vehicle before you start chasing Honda Civic diagnostics.

569 owner complaints
22 involved a crash
6 involved a fire
11 reported injuries
  • ENGINE 65
  • STEERING 161
  • UNKNOWN OR OTHER 160
  • ELECTRICAL SYSTEM 99
  • SERVICE BRAKES 35

6 active recalls

  • STEERING:ELECTRIC POWER ASSIST SYSTEM Sep 2018

    Honda (American Honda Motor Co.) is recalling certain 2017-2018 Honda Civic and CR-V vehicles. The magnet that controls the torque sensor output signal for the electronic power steering system may not be properly secured, allowing the magnet to become dislodged. During a full…

    NHTSA campaign 18V663000
  • EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL Nov 2018

    Honda (American Honda Motor Co.) is recalling certain 2017-2018 Honda Civic Hatchback and Civic Type R vehicles. The owners guide in these vehicles may not have been included or if included, the owner's guide may not have been properly provided required information. As such, t…

    NHTSA campaign 18V817000
  • AIR BAGS Apr 2018

    Honda (American Honda Motor Co.) is recalling certain 2017 Honda Civic Hatchback and Civic Type R vehicles. Driver and front passenger seatback pads sold as replacement service parts were made without slit openings for the seat-mounted side air bags. In the event of a crash nece…

    NHTSA campaign 18V266000
  • POWER TRAIN:DRIVELINE:DRIVESHAFT Nov 2017

    Honda (American Honda Motor Co.) is recalling certain 2017 Honda Civic Sedan and Coupe vehicles. The right halfshaft may have been improperly heat treated, reducing its strength.…

    NHTSA campaign 17V706000

How do I fix P0446 on a 2017 Honda Civic?

About the 2015-2019 Honda Civic

The 2015-2019 Honda Civic was commonly sold with the following powertrains: 2.0L I4, 1.5L Turbo I4, 1.8L I4. Common trims include LX, Sport, EX, Touring.

Why the gas pump clicks off with P0446

The vent valve is what allows the fuel tank to “breathe” during refueling. If the valve is stuck closed, displaced air cannot escape as fuel goes in — pressure builds, fuel splashes back into the filler neck, and the pump nozzle’s auto-shutoff triggers prematurely. If you have to “trickle fill” your tank to get gas in, P0446 (or a related vent code) is the most likely cause.

When P0446 sets with P0455

If P0446 (vent control) sets alongside P0455 (large leak), the root cause is usually one part — the vent valve is stuck open, so the system can never seal for the leak test, which triggers both codes. Replace the vent valve and clear codes; if P0455 returns alone the next monitor run, do a separate small-leak diagnosis.

Trucks and SUVs vs. cars

Under-vehicle mounted vent valves (most trucks, SUVs, and minivans) fail more often than engine-bay mounted ones. They live in a worse environment — road spray, salt, mud, debris. On vehicles with chronic P0446, an upgraded “all-terrain” vent valve or a relocation kit is sometimes worth considering after the second failure.

P0446 on a 2017 Honda Civic: frequently asked questions

What does diagnostic trouble code P0446 mean on a 2017 Honda Civic?

P0446 is set when the engine control module detects that the EVAP vent valve circuit is not behaving as commanded. The vent valve is the normally-open solenoid that lets the charcoal canister breathe — and closes during the EVAP leak test to seal the system. P0446 typically means the vent valve is stuck (mechanically or electrically) so that the system can never seal properly for the leak test.

What are the symptoms of P0446 on a 2017 Honda Civic?

Check Engine Light is illuminated. Difficulty filling the fuel tank (pump clicks off repeatedly). No other drivability problems. Vehicle will fail emissions / smog testing. Sometimes accompanied by P0455 (large leak) on the same scan

What causes P0446 on a 2017 Honda Civic?

Failed EVAP vent valve / vent solenoid (mechanical sticking) (most-common). Dirt, debris, or spider webs clogging the vent valve filter (common). Damaged wiring or connector at the vent valve (common). Failed PCM driver circuit for the vent valve (rare) (rare). Cracked or saturated EVAP charcoal canister (occasional)

Is it safe to drive a 2017 Honda Civic with P0446?

In most cases a 2017 Honda Civic stays drivable for short trips with P0446 active, but it should be diagnosed and repaired promptly — this is a low-severity code. Ignoring it can lead to further damage or a failed emissions test.

Related diagnostic codes

P0446 on other Honda Civic model years