What Redding's Smog Check Requirement Means for Your Vehicle

Redding is in Shasta County, which is part of California's Northern Sacramento Valley air quality region. Vehicles registered in Shasta County must pass a smog check before you can renew your registration — this is a state requirement, not a local one, but how it applies depends on where you live and what you drive.

Not every vehicle needs a smog check every year. The state exempts vehicles that are four model years old or newer, vehicles that are diesel-only (not dual-fuel), motorcycles, and vehicles registered as classic cars or street rods. If your vehicle is older than four model years and runs on gasoline or a gasoline blend, you will need a smog check before your registration renewal date.

The test itself checks your vehicle's emissions systems — the catalytic converter, oxygen sensors, and engine computer — to confirm they are working within state limits. A certified smog technician performs the test at a Bureau of Automotive Repair (BAR) station. The test takes about 30 minutes and costs between $30 and $50, depending on the station.

Key Takeaways

  • Vehicles in Redding that are four model years old or newer do not need a smog check; older gasoline vehicles do.
  • You must pass a smog check before you can renew your vehicle registration with the California Department of Motor Vehicles (DMV).
  • A certified smog technician at a BAR station performs the test, which takes about 30 minutes and costs $30 to $50.
  • If your vehicle fails, you have 30 days to repair it and retest at no additional charge at the same station.
  • You can find BAR-certified stations in Redding through the Bureau of Automotive Repair's online station locator.

Finding a Smog Check Station in Redding

The Bureau of Automotive Repair maintains a searchable database of all certified smog check stations in California. You can search by city or ZIP code to find stations near you in Redding. The database shows each station's address, phone number, and hours of operation.

When you call or visit a station, confirm that it is BAR-certified and that it can test your vehicle type — some stations specialize in certain makes or have equipment for specific vehicle classes. Ask about the cost upfront and whether they accept walk-ins or require an appointment. Many stations in Redding can test you the same day you call.

What Happens During the Smog Check Test

The technician will ask for your vehicle's registration and keys. They will perform a visual inspection of your engine compartment to check that emissions equipment has not been removed or tampered with. They will then connect your vehicle to a dynamometer — a machine that simulates driving — and measure the exhaust gases your engine produces.

The test compares your vehicle's emissions to state standards for your vehicle's model year and engine type. If your emissions are within the limits, you pass and receive a smog check certificate. If your emissions exceed the limits, you fail and receive a repair notice that lists the systems that need attention.

The smog check certificate is valid for 30 days. You must submit it to the DMV when you renew your registration, either online, by mail, or in person at a DMV office. If your certificate expires before you renew, you will need to retest.

What to Do If Your Vehicle Fails the Smog Check

If your vehicle fails, the repair notice will identify which emissions systems are not working properly — for example, a faulty oxygen sensor or a malfunctioning catalytic converter. You have 30 days from the test date to repair your vehicle and return to the same station for a retest at no additional charge.

The cost of repairs depends on what is wrong. Common repairs include replacing spark plugs, fixing vacuum leaks, or replacing a faulty sensor. Some repairs cost $50 to $200; others, like catalytic converter replacement, can cost $500 or more. If the repair cost is very high, you may want to get a second opinion from a trusted mechanic before proceeding.

After you repair your vehicle, return to the same smog check station with your repair notice. The technician will retest your vehicle. If it passes, you receive a new smog check certificate. If it fails again, you have another 30 days to make further repairs and retest.

Timing Your Smog Check Before Registration Renewal

You can take your smog check test up to 90 days before your registration expires. The smog check certificate itself is valid for 30 days, so plan to test within that window before you submit your renewal to the DMV.

Your vehicle registration renewal date is printed on your registration card. The DMV sends a renewal notice about 60 days before that date. If your vehicle needs a smog check, do not wait until the last week — if you fail and need repairs, you will need time to fix the vehicle and retest.

If your registration expires before you complete the smog check and renewal, you cannot legally drive your vehicle. Plan ahead, especially if your vehicle is older or has not been well maintained.

Smog Check Costs and What They Cover

The smog check test itself costs $30 to $50 at most Redding stations. This fee covers the initial test only. If you fail and need a retest, the retest is free at the same station within 30 days. If you go to a different station or test after 30 days, you will pay the full fee again.

The smog check fee does not include any repairs your vehicle may need. Repairs are separate and charged by the repair shop or mechanic. Some stations offer both testing and repair services; others only test. If a station offers repairs, you can ask them to estimate the cost before you authorize the work.

Common Reasons Vehicles Fail Smog Check in Redding

The most common failure reasons are a faulty oxygen sensor, a loose or missing gas cap, a malfunctioning catalytic converter, and a check engine light that is on. A loose gas cap is the easiest fix — tighten it and retest. An oxygen sensor replacement typically costs $100 to $300. A catalytic converter is more expensive but is necessary if it is damaged.

Vehicles that have not been driven regularly or have been sitting unused often fail because the engine computer has not completed its self-diagnostic cycle. Driving the vehicle for 50 to 100 miles on the highway before testing can sometimes help the computer complete its checks and clear minor faults.

If your vehicle fails for a reason you do not understand, ask the technician to explain the repair notice. You can also take the notice to an independent mechanic for a second opinion before spending money on repairs.

Frequently Asked Questions

Do I need a smog check if my vehicle is brand new?

No. Vehicles that are four model years old or newer are exempt from smog checks in California. A vehicle purchased new in 2024 will not need a smog check until 2028. Check your vehicle's registration to confirm its model year.

Can I get a smog check before my registration expires?

Yes. You can test up to 90 days before your registration renewal date. The smog check certificate is valid for 30 days, so plan your test so the certificate does not expire before you submit your renewal to the DMV.

What if I move out of Shasta County after I get a smog check?

Your smog check certificate is valid statewide for 30 days. If you move to another county and renew your registration there within 30 days of your test, you can use the same certificate. If more than 30 days pass, you will need a new test in your new county.

Can I renew my registration without a smog check if my vehicle fails?

No. If your vehicle requires a smog check and fails, you cannot renew your registration until you repair the vehicle, retest, and receive a passing certificate. You cannot legally drive an unregistered vehicle.

Where do I submit my smog check certificate to the DMV?

You can submit your smog check certificate to the DMV online through the California DMV website, by mail to your local DMV office, or in person at a DMV office in Redding. The certificate must be submitted within 30 days of the test date.