Failing your smog test delays your vehicle registration. We work efficiently to diagnose and complete your repairs so you can get your smog certificate and take care of your DMV requirements without extended delays. After completing your repairs, we perform an in-house emissions check to confirm the work resolved the failure before you return for your official smog test. Our technicians are California Bureau of Automotive Repair licensed and trained to diagnose and repair the full range of emissions-related faults identified on smog test certificates.
Failed Emission Testing Repairs
Expert service in Atascadero · Honest diagnostics · Quality parts
Signs Your Vehicle Needs This Service
- Check engine light was on before or during your smog test: an active check engine light is an automatic smog failure in California
- Visible smoke from the exhaust pipe when starting or at idle
- Strong fuel or exhaust smell inside or outside the vehicle
- Vehicle runs rough, hesitates under acceleration, or misfires
- Fuel economy has dropped noticeably over recent months
- You have received a smog test failure certificate listing specific fault codes or readings that did not meet state standards
Failed Emission Testing Repairs
Emissions Failure Diagnosis
Before recommending any repairs, we connect to your vehicle's OBD-II diagnostic system and review the specific failure codes and test readings from your smog certificate. We conduct a targeted inspection of your emissions components to pinpoint the exact cause of the failure.
Oxygen Sensor Replacement
Oxygen sensors monitor exhaust gas composition and signal your engine's computer to adjust the fuel mixture. When they fail, your vehicle runs too rich or too lean, causing elevated hydrocarbon or carbon monoxide readings. We test each sensor individually and replace any that are no longer performing within specification.
Catalytic Converter Service
The catalytic converter converts harmful exhaust gases into less toxic emissions before they leave your tailpipe. A failing converter causes high hydrocarbon and carbon monoxide readings. We inspect your converter and replace it with a quality unit that meets California emissions standards.
EGR System Service
The exhaust gas recirculation system reduces nitrogen oxide emissions by routing exhaust back into the combustion chamber. A stuck, clogged, or failed EGR valve causes elevated NOx readings and smog failures. We service the EGR valve, ports, and related components to restore compliance.
EVAP System Repair
California smog checks include an EVAP pressure test to verify that your fuel vapor system is properly sealed. Leaks from a faulty gas cap to a cracked hose or failed purge valve cause EVAP test failures. We pressure-test your fuel vapor system and locate and repair the source of the leak.
Ignition System Service
Worn spark plugs or failing ignition coils cause misfires that send unburned fuel into the exhaust stream, dramatically raising hydrocarbon emissions. We inspect your ignition system, replace worn plugs and coils, and verify that combustion is clean before sending you back for your retest.
More Services
Why Choose APS Automotive
Honest Diagnostics
We tell you exactly what's wrong and what it takes to fix it. Nothing more, nothing less. No upselling, no surprise charges.
Quality Parts & Warranty
We use only trusted brands and back our work with a solid warranty, giving you peace of mind long after you drive away.
Fast Turnaround
We know you need your vehicle. Our efficient workflow gets you back behind the wheel as quickly as possible without cutting corners.
ASE Certified Technicians
Our 2 ASE-certified technicians bring real expertise. We're also California-licensed smog technicians serving Atascadero since 1992.
Transparent Pricing
You'll receive a detailed estimate before we begin any work. We respect your budget and will never start without your approval.
Clear Communication
No confusing jargon. Just straightforward explanations of what your vehicle needs and why. We're educators, not salespeople.
Ready to Schedule Service?
Request an appointment. We're open Monday through Friday, 7:30am – 5:30pm.
(805) 461-5823