--- title: P0455 and Your Nevada Smog Check | Xpress Smog Check Center url: https://xpresssmogcenter.com/codes/p0455/ 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/) - P0455 # P0455 and your Nevada smog check P0455 means the car's computer found a large leak in the evaporative emission system, the sealed network that keeps gasoline vapor from escaping the fuel tank. It turns on the check engine light, which fails a 1996 or newer light-duty vehicle at a Nevada smog check, and the first thing worth checking is the gas cap. 4.7 stars from 550 Google reviews of the two Reno Xpress Oil & Lube Centers Start at the fuel door. Of all the codes that keep a car from passing a smog check, P0455 is the one most often tied to something you can look at yourself: a gas cap that was left loose, cross-threaded or never put back. The Nevada DMV names a loose gas cap as a common cause when the light comes on suddenly. If the cap is fine, the code points to a larger problem a repair shop will need to find, and the smog rules below explain how to time it. ## At a glance - P0455 is the SAE J2012 code for a large leak in the evaporative emission system. - The DMV names a loose gas cap as a common cause of a check engine light that appears suddenly. - Tightening the cap does not switch the lamp off at once; the computer needs a few drives to recheck. - Any lit lamp fails a 1996 or newer light-duty vehicle at the Nevada OBD test. ## Gas cap first Take the cap off and look at it. Is the seal cracked or missing? Was it clicked tight after the last fill-up? Did someone leave it on the pump? A cap that does not seal leaves the fuel tank open to the air, and to the computer that looks exactly like a big hole in the system. Tighten or replace it, then drive normally. The DMV says tightening the cap may turn the light off after a few days, and EPA's consumer guidance says if the light stays on after a few trips, a technician should look at the vehicle. That delay is the reason to do this well before your registration deadline, not the morning of the test. ## What the code actually describes The generic SAE J2012 wording is: Evaporative emission system leak detected (large leak). Gasoline gives off vapor even when the engine is off. The evaporative emission system, usually shortened to EVAP, collects that vapor in a charcoal canister and later feeds it into the engine to be burned, instead of letting it vent into the air. To make sure the system is sealed, the computer runs a leak test on its own schedule, often after the car has sat for a while. When the system cannot hold the pressure or vacuum the test expects, and the loss is large, it sets P0455. Smaller losses set [P0442](https://xpresssmogcenter.com/codes/p0442/) or [P0456](https://xpresssmogcenter.com/codes/p0456/) instead. ## The smog check result with P0455 stored A leak does not change how the car drives, but it changes the test. Nevada's OBD inspection fails any 1996 or newer light-duty vehicle with the check engine lamp on, whichever system set it. If the cap fixes it, wait for the light to go out and then come in. If not, the DMV still recommends testing: the failed report is the official record of why the car fails and the first document in the waiver path. One thing to skip is clearing the code with a scanner. The EVAP check is one of the self-tests the computer has to repeat, and a cleared memory brings a not ready rejection. ## If the cap was not it Xpress Smog Check Center tests vehicles; the next step is a repair shop. Common causes a repair shop checks include: - The filler neck and its seal where the cap closes. - Cracked or disconnected EVAP hoses. - The charcoal canister and its connections. - A vent or purge valve that stays open when it should close. ## Emissions coverage and the waiver EVAP parts are emission control equipment, and the DMV advises checking with the dealer for federal emissions warranty coverage or a recall before paying; federal law covers some expensive emission components for up to 8 years or 80,000 miles. If repairs in Washoe County do not clear the lamp, the waiver rules apply: receipts showing at least $200 at a 2G licensed authorized station, or at least $200 in related parts bought by the owner within 14 days of the initial test, then a visit to the DMV Emission Lab with both failed certificates. ### Sources - [dmv.nv.gov/emission.htm](https://dmv.nv.gov/emission.htm) (Nevada DMV Emission Control Program: loose gas cap a common cause of a sudden check engine light; read 11/3/26) - [dmv.nv.gov/emission_obd.htm](https://dmv.nv.gov/emission_obd.htm) (Nevada DMV OBD page: lamp on is a fail, test anyway, cleared codes, 8 years / 80,000 miles; read 11/3/26) - [nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P1002K2N.txt](https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P1002K2N.txt) (EPA consumer brochure EPA420-F-02-016: loose gas cap, light stays on after a few trips; read 11/3/26) - [obd-codes.com/p0455](https://www.obd-codes.com/p0455) (public OBD II code reference: P0455 EVAP large leak; read 11/3/26) ### P0455, the generic definition Evaporative emission system leak detected (large leak) 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/) - [P0442 and your Nevada smog check](https://xpresssmogcenter.com/codes/p0442/) - [P0456 and your Nevada smog check](https://xpresssmogcenter.com/codes/p0456/) - [Gas caps and small fixes before a test](https://xpresssmogcenter.com/faq/gas-cap-and-quick-fixes/) - [Check engine light and your smog check](https://xpresssmogcenter.com/smog-check/check-engine-light/) - [Rejected: not ready to test](https://xpresssmogcenter.com/smog-check/not-ready-rejected/) 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 [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/)[P0446 Evaporative emission system vent control circuit Learn more](https://xpresssmogcenter.com/codes/p0446/) ## 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/) ## P0455 questions Still have a question? Call either Reno location or just drive in; there is no appointment to make. ### I tightened the cap. Can I test today? Only if the check engine light is already off. If it is still on, the car will fail; give it a few days of normal driving first. ### Does a large leak mean I smell gas? Not necessarily. The code describes what the leak test measured. If you do smell fuel, have a repair shop look at the car before you drive it much. ### Will the leak show up on any other part of the test? The OBD test reads the computer, and the lamp is what decides it. A stored EVAP code with the lamp on is a fail.