--- title: P0446 and Your Nevada Smog Check | Xpress Smog Check Center url: https://xpresssmogcenter.com/codes/p0446/ business: Xpress Smog Check Center (Located inside Xpress Oil & Lube Center) locations: Reno Northwest: 6100 Mae Anne Ave, Reno, NV 89523, (775) 787-1000, Mon-Fri 8 am-5 pm, Sat 8 am-4 pm, Sun closed; Reno South: 4993 Longley Ln, Reno, NV 89502, (775) 828-6996, Mon-Fri 8 am-5 pm, Sat 8 am-3 pm, Sun closed type: Nevada smog check (vehicle emissions inspection), drive in, no appointment --- Located inside Xpress Oil & Lube Center - Smog check at two Reno locations - Oil change in the same visit - No appointment needed [Xpress Oil & Lube](https://xpressoilandlube.com/) - [Home](https://xpresssmogcenter.com/) - [Codes](https://xpresssmogcenter.com/codes/) - P0446 # P0446 and your Nevada smog check P0446 means the computer found a fault with the vent control of the evaporative emission system, usually the vent valve that lets fresh air into the charcoal canister and seals it for leak tests. The code lights the check engine light, and that is an automatic fail for a 1996 or newer light-duty vehicle in Nevada. 4.7 stars from 550 Google reviews of the two Reno Xpress Oil & Lube Centers The vent valve is a small part with a big role: when it closes, the computer can seal the fuel vapor system and check it for leaks; when it opens, the canister can breathe. If the computer cannot control or confirm that valve, it sets P0446. The car drives the same, but the Reno smog check will not pass while the lamp is on. ## At a glance - P0446 in SAE J2012: Evaporative emission system vent control circuit. - The vent valve opens and closes the canister to fresh air on the computer's command. - Any lit check engine light fails 1996 and newer light-duty vehicles in Nevada (DMV). - Test early in the 90-day window to leave time for a repair and retest. ## The valve behind the code SAE J2012 defines P0446 as "Evaporative emission system vent control circuit." In the EVAP system, fuel vapor from the tank is stored in a charcoal canister. A vent valve, usually near the canister, normally stays open so the canister can breathe. During a self-test the computer closes it to seal the system, then watches pressure or vacuum to look for leaks. The code means something in that vent control is off: the valve may not respond, its electrical circuit may read wrong, or the system may not hold the condition the computer commanded. Because the leak test cannot run properly, the computer reports the fault. ## Questions drivers ask first Is it dangerous? Usually the car runs normally. Will it pass? Not with the lamp on. Can I just clear it? That leads to a not ready rejection, the DMV says, because the computer's self-checks reset. Those three answers shape everything else on this page. One more: does the season matter? The rule does not change with the weather. A lit lamp fails in July and in January, and a passing test is good for 90 days whenever you take it. ## Common causes a repair shop checks Common causes a repair shop checks for P0446 include a vent valve that sticks or has failed electrically, a vent line or filter that is blocked by dirt or debris, damaged wiring or a corroded connector to the valve, and problems at the canister. Vent parts tend to sit low near the tank, where road dirt and winter slush collect. A loose gas cap can also upset EVAP tests, and the DMV lists a loose cap as a common reason the light comes on suddenly, so check it first. ## Testing in Washoe County with this code During the inspection the technician reads the VIN with a bar code reader and connects the analyzer cable to the diagnostic port; the DMV receives the result in real time. A lamp lit by P0446 makes it a fail. That fail is not wasted. The DMV calls the failed test a legal document showing why the vehicle fails; it supports a ten-day movement permit at reduced cost if registration has expired and opens the waiver process if the repair gets costly. Repair spending before that first failed test cannot be counted toward a waiver. ## A practical timeline A passing test is valid for 90 days for a renewal, so testing early leaves time if something turns up. A reasonable order for an EVAP code looks like this. - Check the gas cap and give the car a few days of normal driving. - If the light stays on, test so you have the failed report, then take the car to a repair shop. - After the repair, drive up to a week of mixed city and highway trips; the EVAP monitor can be one of the last to finish. - Come back for the retest. ## Waiver and emissions warranty notes Nevada requires a repair and a passing second test to register. If the vehicle still fails after repairs, the Washoe waiver needs receipts of at least $200 in parts and labor at a 2G licensed authorized station, or at least $200 in parts bought by the owner within 14 days after the initial test, both tied to the failure. See [the waiver page](https://xpresssmogcenter.com/smog-check/smog-waiver/). Before paying, ask the dealer about a recall or the federal emissions warranty, which covers some expensive emission components for up to 8 years or 80,000 miles. The DMV gives no waiver to a vehicle eligible for warranty coverage. ### Sources - [dmv.nv.gov/emission_obd.htm](https://dmv.nv.gov/emission_obd.htm) (Nevada DMV OBD page: test steps, automatic fail, cleared codes and not ready, emissions warranty; read 11/3/26) - [dmv.nv.gov/emission.htm](https://dmv.nv.gov/emission.htm) (Nevada DMV: loose gas cap, 90-day validity, waiver rules; read 11/3/26) - [obd-codes.com/p0446](https://www.obd-codes.com/p0446) (public code reference for the P0446 definition; read 11/3/26) ### P0446, the generic definition Evaporative emission system vent control circuit The SAE J2012 code title. The same P0 code means the same thing on every 1996 and newer OBD II vehicle; the cause behind it differs car to car. ### Your location: Reno South - Call [(775) 828-6996](tel:+17758286996) Mon-Fri 8 am-5 pm, Sat 8 am-3 pm, Sun closed - Address 4993 Longley Ln, Reno, NV 89502 [Directions](https://www.google.com/maps/dir/?api=1&destination=4993+Longley+Ln%2C+Reno%2C+NV+89502&destination_place_id=ChIJc5xNCcI_mYARXjHn3y79iJw) ### Related - [Check engine codes](https://xpresssmogcenter.com/codes/) - [P0440 and your Nevada smog check](https://xpresssmogcenter.com/codes/p0440/) - [P0441 and your Nevada smog check](https://xpresssmogcenter.com/codes/p0441/) - [P0456 and your Nevada smog check](https://xpresssmogcenter.com/codes/p0456/) - [Rejected: not ready to test](https://xpresssmogcenter.com/smog-check/not-ready-rejected/) - [Smog waiver in Washoe County](https://xpresssmogcenter.com/smog-check/smog-waiver/) Located inside Xpress Oil & Lube Center Both smog check locations sit inside an Xpress Oil & Lube Center, the locally owned Reno drive-in that has served this town since 1983. Drive in, no appointment; get your oil changed in the same visit. [About us](https://xpresssmogcenter.com/about/) ## More evaporative emission (evap) system codes [P0455 Evaporative emission system leak detected (large leak) Learn more](https://xpresssmogcenter.com/codes/p0455/)[P0442 Evaporative emission system leak detected (small leak) Learn more](https://xpresssmogcenter.com/codes/p0442/)[P0456 Evaporative emission system leak detected (very small leak) Learn more](https://xpresssmogcenter.com/codes/p0456/)[P0441 Evaporative emission system incorrect purge flow Learn more](https://xpresssmogcenter.com/codes/p0441/)[P0440 Evaporative emission system malfunction Learn more](https://xpresssmogcenter.com/codes/p0440/) ## If the light is on at your smog check [### Check engine light and your smog check Why a lit check engine light decides the test. Learn more](https://xpresssmogcenter.com/smog-check/check-engine-light/)[### Failed a smog check What the failed report means and the steps that follow. Learn more](https://xpresssmogcenter.com/smog-check/failed-smog-check/)[### Repair and retest Getting the repair done and coming back for the second test. Learn more](https://xpresssmogcenter.com/smog-check/repair-and-retest/)[### Rejected: not ready to test Why a car can be turned away without failing. Learn more](https://xpresssmogcenter.com/smog-check/not-ready-rejected/) ## P0446 questions Still have a question? Call either Reno location or just drive in; there is no appointment to make. ### Is P0446 the same as a leak code? Not exactly. Leak codes report a leak the computer measured. P0446 says the vent control itself has a fault, which can stop the leak test from running. ### Could filling the tank have caused it? Overfilling past the pump's click is sometimes blamed for EVAP trouble. A repair shop can tell you whether it applies to your car. ### What other EVAP codes are common? P0440, P0442, P0455 and P0456 are related. Start at [our P0440 page](https://xpresssmogcenter.com/codes/p0440/).