Smog check FAQ
Everything Modesto drivers ask us.
Straight answers about test-only smog checks, STAR certification, pricing, California smog rules and what to do if you fail. Se habla español.
Smog checks near you
Smog checks near you.
Where can I get a smog check near me in Modesto?
AZ Tech Smog Check is at 1324 N Carpenter Rd, Modesto, CA 95351 — a STAR-certified, test-only station that does every DMV smog for all vehicles. Walk in, no appointment needed.
Is there a STAR test-only smog station near me in Modesto?
Yes — AZ Tech Smog Check on N Carpenter Rd is a STAR-certified, test-only station, so we can inspect and certify exactly what the DMV asks for.
Do I need an appointment, or can I just walk in?
Walk-ins are welcome — no appointment needed. Short on time? Call ahead at (209) 577-1644 and we’ll get you in fast.
Which areas do you serve?
Drivers from Modesto and nearby Salida, plus the surrounding Stanislaus County communities.
Where exactly is AZ Tech Smog Check located?
At 1324 N Carpenter Rd, Modesto, CA 95351, on N Carpenter Rd just off Highway 99, with parking at the door.
What kinds of vehicles can you smog?
All of them — cars, SUVs, pickups, vans and motor homes, in gas, diesel and hybrid, for every DMV reason.
Pricing & coupon
Pricing and the coupon.
How much does a smog check cost in Modesto?
It’s $39.75 for most 2000-and-newer passenger cars, plus the $8.25 state certificate that’s only added when your vehicle passes. Diesels, older vehicles and larger trucks are a little more — just call for your price.
How does the $39.75 coupon work?
Show it on your phone or print it and present it before we start. It applies to 2000-and-newer passenger cars and can’t be combined with other offers.
Is the $8.25 certificate fee included in the coupon price?
No — the $8.25 state certificate is separate, and it’s only charged when your vehicle passes.
Which vehicles qualify for the $39.75 price?
Most 2000-and-newer passenger cars. Diesels, older vehicles and larger trucks carry a small add-on over the coupon price.
Why do smog prices vary by vehicle?
Older vehicles, diesels and larger trucks take more time and a different test procedure, so they cost a bit more than the standard passenger-car rate.
Can I show the coupon on my phone, or do I have to print it?
Either works — show it on your phone or bring a printout. You can even email it to yourself from our coupon page.
STAR stations
STAR stations.
What is a STAR smog station?
A smog station the DMV holds to higher Bureau of Automotive Repair standards and monitors closely, and that’s authorized to certify DMV-directed vehicles.
Is AZ Tech Smog Check STAR certified?
Yes — we’re a STAR-certified, test-only station (BAR #263716), and you can verify our license with the California Department of Consumer Affairs.
Why does my DMV renewal notice say “STAR station required”?
The DMV directs a share of vehicles to STAR stations. It doesn’t mean anything is wrong with your car — your certificate just has to come from a STAR station like ours.
What’s the difference between a STAR smog check and a regular one?
The test itself is the same; the difference is authorization. Only a STAR station can certify a DMV-directed vehicle. If your notice doesn’t say STAR, you can test anywhere — including here.
Can you also test vehicles that aren’t STAR-directed?
Yes — we inspect and certify both STAR-directed vehicles and regular, non-directed vehicles.
What happens if I go to a non-STAR station when STAR was required?
The DMV won’t accept that certificate for a directed vehicle, so you’d have to test again at a STAR station. Come to us first and skip paying twice.
Test-only
Test-only stations.
What is a test-only smog station?
A station licensed only to inspect and certify vehicles — not to repair them.
Does a test-only station do repairs?
No. Because we can’t sell you repairs, there’s no upsell — just an honest test at our lowest price.
Why would I choose a test-only station?
No conflict of interest. Our only job is a fair inspection, so you get a straight result with nothing added on.
If I fail, can I get repairs elsewhere and come back for a retest?
Yes — have the repairs done wherever you like, then bring the vehicle back and we’ll retest it.
What’s the difference between test-only and test-and-repair?
A test-and-repair shop can both test and fix cars; a test-only station like ours only inspects and certifies. Some DMV-directed vehicles must use a test-only or STAR station.
DMV & registration
Registration and the DMV.
Does my passing result go straight to the DMV?
Yes — we transmit your passing certificate to the DMV/BAR electronically at no extra charge, so your registration can go through.
How soon does the DMV get my result?
Within minutes of passing — it’s filed electronically while you’re still here.
What should I bring to my smog check?
Just your vehicle and, if you have it, your DMV renewal notice. For a transfer or out-of-state car, bring the title or current registration.
Can I get smogged without my DMV renewal notice?
Yes — we can look your vehicle up without it.
How often does California require a smog check?
Most vehicles need one every two years for registration renewal, plus when a vehicle is sold or first registered in California. Your DMV notice tells you when yours is due.
If your vehicle fails
If your vehicle fails.
What happens if my vehicle fails the smog check?
We’ll explain exactly why it failed and what to repair, in plain language. Once it’s fixed, bring it back for a retest.
What are the most common reasons a car fails smog?
An illuminated check-engine light, incomplete readiness monitors, or worn emissions parts like the catalytic converter, oxygen sensors or EVAP system.
Can I pass with the check-engine light on?
No — an illuminated check-engine light is an automatic fail on any OBD-II vehicle. Have it diagnosed and repaired before you test.
What is a gross polluter, and can you certify one?
A gross polluter is a vehicle emitting well above the limit. As a STAR station we can inspect and certify it once it’s been repaired and passes.
Can I get help paying for repairs if I fail?
You may qualify for California’s Consumer Assistance Program (CAP): up to $500 toward emissions repairs for eligible motorists, or $1,000 to retire a high-polluting vehicle. See our resources page for details.
How soon can I come back for a retest after repairs?
As soon as the repairs are done and the vehicle has been driven enough for the readiness monitors to reset — usually a short drive cycle.
Tips to pass
Tips to pass.
How do I give my car the best chance of passing?
Keep up regular maintenance per your owner’s manual, don’t tamper with emissions equipment, and drive it 15 minutes before the test so it’s warmed up.
Should I drive my car before the test, and for how long?
Yes — about 15 minutes. A warm engine and hot catalytic converter burn cleaner, and a cold start can fail a test the car would otherwise pass.
Should I disconnect my battery before a smog check?
No. Disconnecting or recently replacing the battery resets the OBD-II readiness monitors, and the car can’t pass until they finish re-running.
What are OBD-II readiness monitors, and what does “not ready” mean?
They’re self-checks your car runs on its emissions systems. If too many aren’t complete, the car reads “not ready” and can’t be certified until it’s driven enough to finish them.
Should I clear the check-engine light or codes before coming in?
No — clearing codes resets the readiness monitors, which fails the test until they complete again. Fix the underlying issue instead.
During your inspection
During your inspection.
How long does a smog check take?
Most eligible vehicles are done in about 15 minutes, and you can wait while we test.
What happens during a California smog inspection?
We connect to your vehicle’s OBD-II system, check the emissions components and confirm nothing has been tampered with, then verify it meets California standards. On a pass, we file the certificate with the DMV.
Can I wait while my vehicle is tested?
Yes — most visits are quick, so you’re welcome to wait and drive off with your result in hand.
Vehicles & exemptions
Vehicles and exemptions.
Do you smog diesel vehicles and diesel trucks?
Yes — we’re licensed to test eligible diesels, including diesel pickups and SUVs. Diesels carry a small add-on over the passenger-car coupon price.
Do hybrids need a smog check, and do you test them?
Yes — gasoline-electric hybrids, including most plug-in hybrids, need smog checks in California, and we test them.
Do electric vehicles like a Tesla need a smog check?
No — battery-electric vehicles are exempt from California smog inspections, so a Tesla doesn’t need one.
Can you smog SUVs, pickups, vans and RVs or motor homes?
Yes — we test SUVs, pickups, vans and motor homes. Larger vehicles carry a small add-on over the coupon price.
Do out-of-state vehicles need a smog check to register in California, and do you do them?
Yes — bringing a vehicle into California for registration requires a smog inspection, and we handle out-of-state vehicles, including from Nevada and Arizona, every day.
Do I need a smog check when buying or selling a vehicle?
Usually yes — a change-of-ownership sale needs a smog certificate, generally the seller’s responsibility, to transfer the title. We do those every day.
What model-year vehicles need a smog check in California?
Most gasoline vehicles from 1976 and newer, and most diesels from 1998 and newer up to 14,000 lbs. Newer gas vehicles are exempt for their first eight model years.
What vehicles are exempt from California smog inspections?
Gasoline vehicles 1975 and older, electric vehicles, and motorcycles are generally exempt; diesel rules differ. If you’re unsure, give us a call.
Se habla español
Se habla español.
¿Cuánto cuesta un smog check en Modesto?
Son $39.75 para la mayoría de los autos del año 2000 o más nuevos, más $8.25 del certificado estatal, que solo se cobra cuando el vehículo aprueba. Los diésel, vehículos más viejos y camionetas grandes cuestan un poco más.
¿Necesito cita o puedo llegar sin cita?
Atendemos sin cita — no necesita hacer una. Si tiene prisa, llame al (209) 577-1644 y lo atendemos rápido.
¿Dónde hay una estación de smog STAR cerca de mí en Modesto?
AZ Tech Smog Check, en 1324 N Carpenter Rd, Modesto, CA 95351 — una estación STAR “test-only” (solo prueba). Atendemos Modesto y Salida.
¿Qué es una estación STAR?
Es una estación de smog que cumple con los estándares más altos del Bureau of Automotive Repair y está autorizada para certificar los vehículos que el DMV dirige a una estación STAR. Somos STAR (BAR #263716).
¿Qué significa una estación “Test-Only” (solo prueba)?
Es una estación con licencia solo para inspeccionar y certificar, no para reparar. Como no vendemos reparaciones, no hay presión de venta — solo una prueba honesta al mejor precio.
¿Hacen smog a diésel, camionetas e híbridos?
Sí — probamos todo tipo de vehículos: gasolina, diésel e híbridos, además de camionetas, vans y casas rodantes. Los diésel y vehículos grandes tienen un pequeño cargo adicional.
¿Qué pasa si mi vehículo no pasa el smog?
Le explicamos exactamente por qué falló y qué reparar. Después de la reparación, regrese para una nueva prueba — y podría calificar para hasta $500 de ayuda para reparaciones a través del programa estatal CAP.
¿Envían el resultado al DMV electrónicamente?
Sí — enviamos su certificado de aprobación al DMV electrónicamente, sin cargo adicional, para que pueda renovar su registración.
¿Cuánto tiempo toma el smog check?
La mayoría de los vehículos se completan en unos 15 minutos, y puede esperar mientras hacemos la prueba.
¿Atienden en español?
Sí, se habla español. Le explicamos cada paso del smog check con gusto, sin cita y al precio más bajo.
$39.75 smog check in Modesto. Se habla español.
1324 N CARPENTER RD · STAR STATION · TEST-ONLY
(209) 577-1644