A code is a clue. We find the cause.
Check Engine Light Diagnostics
Free code readers give you a number, not an answer. P0420 does not mean buy a catalytic converter and P0300 does not mean buy plugs. We scan every module, review freeze-frame data, then test the circuit or component the code is pointing at.
We have deep experience with Japanese makes: Honda VTEC and VCM issues, Toyota VVT-i and AFM sensors, Nissan CVT and VQ timing chains, Subaru misfire and head gasket patterns, and Mazda direct-injection carbon buildup. Diagnostic time is billed honestly at our hourly rate and credited toward the repair when we do the work. You get the fault, the evidence and a written estimate before anything is replaced.
What's included
Scope of work
- All-module scan: engine, transmission, ABS, body, aftertreatment
- Freeze-frame and live-data review under load
- Fuel-trim, misfire and injector contribution analysis
- Circuit testing with voltage drop and scope where needed
- Smoke testing for vacuum, boost and EVAP leaks
- Sensor verification against known-good values
- Written findings with photos and a repair estimate
- Post-repair verification drive and monitor completion
Symptoms we fix
Sound familiar?
- Check engine, wrench or service light on or flashing
- Rough idle, misfire, hesitation or stalling
- Loss of power or limp mode
- Poor fuel economy with no obvious cause
- Light returns after another shop cleared it
- Failed smog because of a stored code
How we work it
The four steps, every time
- 01
Scan
Every module, stored and pending codes, plus freeze-frame conditions.
- 02
Reproduce
We drive it and log data until the fault shows itself.
- 03
Pinpoint
Component or circuit is proven bad before it goes on the estimate.
- 04
Verify
After repair we re-drive, confirm the fix and complete the monitors.
Questions
Straight answers
The parts store scanned it free. Why pay you?
They read a code. We identify which component or circuit actually caused it, which is the part that saves you money.
Is it safe to drive with the light on?
A steady light usually means drive it in soon. A flashing light means stop driving — that is an active misfire that can destroy a converter.
Do you charge again if the light comes back?
If it is the same fault we diagnosed and repaired, it is our problem to make right.
Watch the spot
Diagnostic & Repair Service
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.
ViewFailed Smog Diagnosis & Repair
Emissions diagnostics and repair for vehicles that failed the smog test, plus a free retest.
ViewCatalytic Converter Replacement
CARB-compliant converters installed and verified so the vehicle passes California smog.
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.