Failed somewhere else? We diagnose the real cause instead of parts-cannoning it.
Failed Smog Diagnosis & Repair
A failed smog report is a list of symptoms, not a diagnosis. High NOx, high HC, a monitor that will not set, an EVAP leak, a P0420 catalyst code — each has several possible causes, and replacing a converter to chase a fuel-trim problem is an expensive way to fail twice.
We read the failure report, verify with live data and pinpoint testing, then quote the repair that actually returns the vehicle to spec. Retest here is free after we do the qualifying work.
What's included
Scope of work
- Full read of the state failure report line by line
- OBD-II live data, fuel trim and readiness monitor analysis
- Oxygen and air/fuel ratio sensor testing
- Catalytic converter efficiency testing before replacement
- EVAP smoke testing for leaks and gas cap faults
- EGR, PCV, ignition and vacuum leak repair
- Drive cycle to set readiness monitors
- Free retest after qualifying repairs
Symptoms we fix
Sound familiar?
- Failed for high HC, CO or NOx
- P0420 / P0430 catalyst efficiency code
- Not-ready monitors after a battery disconnect
- EVAP or gas cap failure
- Check engine light on at the test
- Gross polluter notice from the state
How we work it
The four steps, every time
- 01
Read the report
We go through your failure printout with you and explain what each measured number means.
- 02
Test
Live data, sensor testing and smoke testing isolate the fault before anything is replaced.
- 03
Repair
You get a written estimate first. We repair the cause, not the code.
- 04
Retest
Drive cycle to set monitors, then a free retest at our own STAR lane.
Questions
Straight answers
Do I always need a new catalytic converter?
No. We test converter efficiency and upstream causes first. Many 'bad cat' codes are actually misfires, sensor faults or exhaust leaks.
Is there financial help for smog repairs?
California's Consumer Assistance Program can help qualifying owners with repair costs. We will point you to the application and document the repair properly.
Is the retest really free?
Yes, when we perform the qualifying repair here.
Related terms
What people search for this job
Keep reading
STAR Certified Smog Check
Official STAR station smog inspection for every California vehicle, including STAR-directed cars.
ViewCatalytic Converter Replacement
CARB-compliant converters installed and verified so the vehicle passes California smog.
ViewEngine Diagnostics & Electrical
Check engine lights, drivability faults, no-starts and electrical gremlins traced to the actual cause — all makes, with deep experience on Japanese vehicles.
ViewFree estimates · Free retest after qualifying smog repairs
Get a straight answer on your vehicle.
Tell us what it's doing. We'll tell you what it takes — in writing, before any work starts.