Diesel truck questions
Under DMV rules a diesel based in urban Washoe needs a yearly test when its manufacturer's gross vehicle weight rating is 14,000 pounds or less. Call the service center before you bring a diesel, so the staff can tell you what to expect.
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Diesel rules depend on weight and on where the truck is based. This page explains the DMV's rules and sends you to the phone before you make the trip.
Do diesels need a smog check in Reno?
Yes, when they meet all of the DMV's criteria: a GVWR of 14,000 pounds or less, based in the urban areas of Clark or Washoe, and model year 1968 or newer. New vehicles are exempt for the first three registrations and tested at the fourth.
What is in a light-duty diesel test?
The DMV describes a comprehensive inspection with a dynamometer test, an opacity test measuring exhaust density and a visual inspection of emission components.
Which weight does the DMV use?
The manufacturer's gross vehicle weight rating. The DMV says it may differ from the declared weight used for registration fees, so check your renewal notice to see whether a smog check is required.
What about a diesel over 14,000 pounds?
Those are not required to take the annual smog check but are subject to statewide roadside enforcement, based on the DMV. Sworn officers use the SAE J1667 snap acceleration test for exhaust opacity at traffic stops, highway check sites and weigh stations.
Does the roadside rule cover trucks from other states?
Yes. The DMV says the standards apply to all vehicles traveling in Nevada, including those registered in other states.
Can I get my diesel tested at your Reno locations?
Please call the service center before you bring a diesel. Reno Northwest is at (775) 787-1000 and Reno South is at (775) 828-6996. The staff will tell you what to expect for your truck.
How long is a diesel test result good for?
The DMV says 90 days for most tests and 180 days when the vehicle was purchased from a Nevada dealer.
Is a diesel pickup treated like a gas pickup?
Not the same way. Gasoline vehicles get a tailpipe or OBD inspection depending on model year, while light-duty diesels get the dynamometer, opacity and visual test described above.
What if I am unsure whether my diesel needs a test?
The DMV says to contact its emission lab. In Reno that is (775) 684-3580, at 9155 Double Diamond Pkwy. For heavy-duty diesel questions the DMV lists (775) 684-3562.
Where can I read more about diesel testing?
See the diesel smog check page and the diesel opacity and dynamometer guide.
Does a diesel pickup that tows a trailer count the trailer?
The DMV rule uses the vehicle's own manufacturer's GVWR. Look at the sticker on the driver's door jamb and compare it with 14,000 pounds.
What if my renewal notice does not list a test?
Follow the notice. The DMV says to check your renewal notice to see if a smog check is required, since the weight rating on file decides it.
Before you drive the truck over
Have your GVWR and model year handy, plus your renewal notice. A short phone call to the service center saves a trip, and it lets the staff answer questions about your particular truck.
If your diesel is over 14,000 pounds, the annual test does not apply under the DMV rules, but the roadside opacity standards do, and they apply statewide.
Why the dynamometer and opacity steps exist
A light-duty diesel is checked differently from a gas car because its pollution looks different. The DMV measures exhaust density with the opacity test, and the dynamometer lets the truck run under load during the test. The visual inspection looks over the emission components.
Because the equipment and the vehicle size matter, the safest move is a phone call before you drive in. Ask the service center at (775) 787-1000 or (775) 828-6996 about your specific truck.
Sources
- dmv.nv.gov/emission_diesel.htm (Nevada DMV diesel testing and enforcement; read 10/19/26)
- dmv.nv.gov/emission.htm (Nevada DMV Emission Control Program; read 10/19/26)
More questions by topic
Who needs a smog check in NevadaWhere in Washoe County a test is requiredThe renewal notice and the smog line on itYour result and the DMV linkHow long a passing test is good forRenewing your registration with the smog checkWhat a smog check costsDriving in without an appointmentHours and the quiet times to come inWhich service center to useAn oil change in the same visitCheck engine light questionsAfter a failed testSmog waiver questionsNot ready and rejected resultsAfter a battery change or a repairGas caps and small fixes before a testInsurance trackers and OBD port devicesNew vehicles and the first three registrationsHybrid and electric vehicle questionsDiesel truck questionsMotorhomes and heavier gas trucksClassic car and Old Timer plate questionsMotorcycles and other exempt vehiclesMoving to Reno or SparksLeaving Nevada or living away part of the yearMilitary members and studentsPrivate party salesBuying from a Nevada dealerSmoking vehicles and visible exhaustEngine swaps and modified vehiclesRegistered outside the Washoe testing area
Your location: Reno South
- Call(775) 828-6996Mon-Fri 8 am-5 pm, Sat 8 am-3 pm, Sun closed
- Address4993 Longley Ln, Reno, NV 89502
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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.
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Two Reno locations, no appointment
Drive in for your smog check. No appointment.
Two Reno locations inside Xpress Oil & Lube Center. Questions first? Send the form and the location you pick answers during business hours.
4.7 stars from 550 Google reviews of the two Reno Xpress Oil & Lube Centers
- No appointment needed
- Located inside Xpress Oil & Lube Center
- Two Reno service centers
- Results go to the DMV electronically