P0446 on a 2017 Toyota Tacoma
EVAP Vent Control Circuit Fault
P0446 on a 2017 Toyota Tacoma 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.
What does P0446 mean on a 2017 Toyota Tacoma?
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 Toyota Tacoma generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2015 through 2019.
Is it safe to drive a 2017 Toyota Tacoma with P0446?
In most cases a 2017 Toyota Tacoma 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 Toyota Tacoma?
- 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 Toyota Tacoma?
| 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 Toyota Tacoma
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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
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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
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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
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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)
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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
NHTSA complaints & recalls for the 2017 Toyota Tacoma
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2017 Toyota Tacoma. Use these to gauge how common a problem is on your specific vehicle before you start chasing Toyota Tacoma diagnostics.
- POWER TRAIN 67
- ENGINE 35
- UNKNOWN OR OTHER 35
- SERVICE BRAKES 30
- STRUCTURE 25
5 active recalls
- EQUIPMENT:OTHER:LABELS Dec 2017
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2017-2018 Toyota 4Runner and Tundra, 2018 Toyota Highlander, RAV4 and Lexus GX460 and 2017 Toyota Sienna and Tacoma vehicles. These vehicles may have incorrect load carrying capacity modification labels. As…
NHTSA campaign 17V831000 - ENGINE Jun 2017
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2016-2017 Tacoma vehicles equipped with a six-cylinder engine. The affected vehicles have a crank position sensor that may malfunction, potentially resulting in an engine stall.…
NHTSA campaign 17V356000 - POWER TRAIN:DRIVELINE:DIFFERENTIAL UNIT Apr 2017
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2016-2017 Tacoma vehicles. Oil may leak from the area where the rear differential carrier is assembled to rear axle housing.…
NHTSA campaign 17V285000 - SERVICE BRAKES, HYDRAULIC:POWER ASSIST:VACUUM Apr 2018
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain 2018 Toyota Camry and Highlander vehicles, 2017 Toyota Sienna and Tacoma vehicles and 2017 Lexus RX350 vehicles. During the manufacturing process, the oil galley in the rotor for the brake booster vacuum pump…
NHTSA campaign 18V211000
How do I fix P0446 on a 2017 Toyota Tacoma?
- Replace the EVAP vent valve / vent solenoid
- Clean the vent valve filter and inspection port
- Repair damaged wiring or connector at the vent valve
- Replace the charcoal canister assembly
About the 2015-2019 Toyota Tacoma
The 2015-2019 Toyota Tacoma was commonly sold with the following powertrains: 2.7L I4, 3.5L V6, 4.0L V6. Common trims include SR, SR5, TRD Sport, TRD Off-Road, Limited.
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 Toyota Tacoma: frequently asked questions
What does diagnostic trouble code P0446 mean on a 2017 Toyota Tacoma?
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 Toyota Tacoma?
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 Toyota Tacoma?
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 Toyota Tacoma with P0446?
In most cases a 2017 Toyota Tacoma 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.