--- title: How the OBD Smog Test Works in Nevada | Xpress Smog url: https://xpresssmogcenter.com/smog-check/obd-test/ 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/) - [Smog checks](https://xpresssmogcenter.com/smog-check/) - How the OBD smog test works # How the OBD smog test works Nevada tests 1996 and newer light-duty vehicles by reading the car's own on-board diagnostics computer rather than measuring the tailpipe. The technician scans the VIN, plugs an analyzer into the diagnostic port under the dash, and the result goes to the DMV in real time; the DMV says most tests take five minutes or less. 4.7 stars from 550 Google reviews of the two Reno Xpress Oil & Lube Centers - VIN scan The emissions technician scans the vehicle identification number with a bar code reader, for accurate records and identification. - OBD connection A cable from the analyzer plugs into the vehicle's OBD port, usually under the dashboard. No other connection or probe is needed. - Quick analysis The analyzer talks to the car's computer and reads its emission data and diagnostic information. - Result The system shows pass or fail and helps the technician pinpoint a malfunction. The result goes to the DMV in real time. OBD II, short for On-Board Diagnostics, second generation, is a standardized computer system built into every 1996 and newer light-duty vehicle sold in the U.S. It constantly watches the engine and the emission controls. Nevada's smog test simply asks it what it has seen. Here is the test step by step, as the Nevada DMV describes it. ## At a glance - For 1996 and newer light-duty cars and trucks (Nevada DMV). - No probe in the tailpipe: one cable to the diagnostic port. - Most tests take five minutes or less, according to the DMV. - Results go to the DMV in real time, so you can usually renew right after. ## What the analyzer reads The car's computer stores two things the test cares about. First, whether any emission-related fault is active, the kind that turns on the check engine light. Second, whether its readiness monitors have finished, the self-checks it runs on systems like the catalytic converter and oxygen sensors. A lit check engine light means a fail. Unfinished monitors mean the car is not ready and the test is rejected, which is not a fail. ## Why Nevada uses it The DMV lists the advantages: speed, with most tests done in five minutes or less; accuracy, a precise digital report of the engine's health; cost, because it is less expensive than the dynamometer tests used in some other states; and real-time data, with results sent instantly to the DMV. It also catches problems early. The DMV points out that OBD detects failing emission components before you notice a change in how the car drives. ## Before you pull in Unplug anything in the diagnostic port. Insurance trackers and other driving monitors live there, and the DMV says technicians are required to fail any vehicle that has a device plugged into the OBD port during the inspection. If the battery was recently replaced or disconnected, give the car up to a week of normal driving first, so the computer can finish its self-checks. ## Which vehicles get it 1996 and newer light-duty vehicles: gasoline cars, SUVs, vans and pickups up to 8,500 pounds. Vehicles from 1995 and earlier and all heavy-duty vehicles keep the traditional two-speed tailpipe test, and light-duty diesels have their own test with a dynamometer and an opacity reading. ## After the test Pass: renew right away, at a station that offers renewal, online through MyDMV, or at a DMV Now kiosk minutes later. The pass is valid 90 days. Fail: you get a report detailing why, and the vehicle needs repairs and a retest. Rejected: drive a few days and come back. ## What it means for your visit Because the test is a computer reading, the car does not need to be warmed up on a machine or run at speed in the bay. Pull in, hand over the keys, and the technician handles the VIN scan and the connection. If you want to renew in the same visit, bring your renewal notice. If you also want an oil change, ask; both locations are inside an Xpress Oil & Lube Center. ### Sources - [dmv.nv.gov/emission_obd.htm](https://dmv.nv.gov/emission_obd.htm) (Nevada DMV On-Board Diagnostics page: steps, five-minute tests, OBD port devices, results; read 10/19/26) - [dmv.nv.gov/emission.htm](https://dmv.nv.gov/emission.htm) (Nevada DMV: vehicle classifications, light and heavy duty; read 10/19/26) ### 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) ### What a customer said Reno South We use them for Smog and Oil changes. Always fast and professional! [All smog check reviews](https://xpresssmogcenter.com/reviews/) ### Related - [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/) - [Insurance trackers and OBD port devices](https://xpresssmogcenter.com/faq/obd-port-devices/) - [Readiness monitors, in plain English](https://xpresssmogcenter.com/guides/readiness-monitors/) - [1968 to 1995 vehicles: the tailpipe test](https://xpresssmogcenter.com/smog-check/older-vehicles-tailpipe-test/) 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/) ## Related situations [### 1968 to 1995 vehicles: the tailpipe test How older cars and heavy-duty trucks are tested. Learn more](https://xpresssmogcenter.com/smog-check/older-vehicles-tailpipe-test/)[### Diesel smog check rules Which diesels test in Washoe County and how. Learn more](https://xpresssmogcenter.com/smog-check/diesel-smog-check/)[### Hybrids and electric vehicles When a hybrid starts testing and why EVs never do. Learn more](https://xpresssmogcenter.com/smog-check/hybrid-and-electric-vehicles/)[### New vehicle exemption The first three registrations of a new car. Learn more](https://xpresssmogcenter.com/smog-check/new-vehicle-exemption/)[### Classic plates and other exemptions Classic Vehicle, Classic Rod, Old Timer and the rest of the exempt list. Learn more](https://xpresssmogcenter.com/smog-check/classic-and-exempt-vehicles/) ## How the OBD smog test works: questions Still have a question? Call either Reno location or just drive in; there is no appointment to make. ### Does the OBD test use a treadmill or a probe in the exhaust? No. It is a plug-in reading of the car's computer. Dynamometer testing is used for light-duty diesels. ### Where is the OBD port? Usually under the dashboard on the driver's side, according to the DMV. ### Can the test damage my car? The analyzer only reads data through the port; it is the same connection a repair shop uses to read codes. ### Does a 1996 truck over 8,500 lb get the OBD test? The DMV says all heavy-duty vehicles keep the two-speed tailpipe method, so a gasoline vehicle over 8,500 lb gets the tailpipe test. ## Two Reno locations, inside Xpress Oil & Lube Center [Reno Northwest smog check](https://xpresssmogcenter.com/locations/reno-mae-anne/)[Reno South smog check](https://xpresssmogcenter.com/locations/reno-longley/)