Check Engine Light Repair Near Me
TL;DR - Quick Answer:
Check engine light on? We offer free diagnostic scans and same-day check engine light repair in Rohnert Park & Sonoma County. ASE certified technicians with professional-grade scan tools diagnose the root cause — not just the code. BBB A+ rated, nearly 30 years experience. Call (707) 584-7727 for immediate diagnosis.
That dashboard warning light doesn't have to mean a massive repair bill. Our ASE certified technicians use professional-grade diagnostics to find the real problem, explain your options in plain language, and fix it right the first time.
Common Check Engine Light Codes We Diagnose
TL;DR: These are the 6 most common trouble codes we see. Each requires proper diagnosis to avoid replacing parts you don't need. Browse all codes in our OBD-II database.
Catalytic Converter Efficiency
Most common code. Could be the catalytic converter, oxygen sensors, or exhaust leaks. Professional diagnosis prevents expensive misdiagnosis.
Engine Misfire
Random or cylinder-specific misfire. Causes include spark plugs, ignition coils, fuel injectors, or compression issues. A flashing CEL with this code is urgent.
System Too Lean
Engine running lean means too much air or not enough fuel. Common causes include vacuum leaks, MAF sensor, fuel pump, or intake gasket issues.
EVAP System Leak
Evaporative emission system leak — often as simple as a loose gas cap. Can also be a cracked hose, faulty purge valve, or charcoal canister issue.
Thermostat/Coolant Temp
Coolant temperature below thermostat regulating range. Usually means the thermostat is stuck open. Affects fuel economy and heater performance.
Large EVAP Leak
Large leak in the evaporative emission system. Check your gas cap first — if it's loose or the seal is damaged, that's often the fix. Otherwise needs professional diagnosis.
Solid vs. Flashing Check Engine Light
TL;DR: A solid light needs attention soon. A flashing light needs attention right now. Here's how to tell the difference and what to do.
Solid Check Engine Light
- Non-emergency but needs diagnosis soon
- Safe to drive to the shop carefully
- Could be sensors, emissions, or minor issues
- Schedule diagnosis within a few days
Flashing Check Engine Light
- URGENT — active engine misfire
- Can damage catalytic converter quickly
- Reduce speed and avoid heavy acceleration
- Get to a repair shop immediately
Read our detailed guide: Flashing vs. Solid Check Engine Light — What It Means
Why Professional Diagnosis Matters
A parts store scan tells you the code. We tell you the cause. That difference can save you hundreds in unnecessary parts:
- P0420 could be O2 sensor, cat, or exhaust leak — not always the converter
- Misfire codes need root-cause analysis, not just new spark plugs
- Lean codes can be vacuum leaks, sensors, or fuel system issues
- We use live data analysis, not just code readers
Check Engine Light Diagnostic Services
TL;DR: From free code scans to comprehensive diagnostics, we offer the right level of service for your situation.
| Service | Estimate |
|---|---|
| OBD-II Code Scan | FREE |
| Comprehensive Diagnostics | Call for quote |
| Oxygen Sensor Replacement | Call for quote |
| Catalytic Converter Service | Call for quote |
| Spark Plug / Ignition Coil Replacement | Call for quote |
| MAF / MAP Sensor Replacement | Call for quote |
| EVAP System Repair | Call for quote |
| EGR Valve Service | Call for quote |
Repair costs vary by vehicle make/model and specific issue. Call (707) 584-7727 for a free scan and estimate.
Our 5-Step Diagnostic Process
TL;DR: We don't guess. We diagnose systematically, explain clearly, then fix it right the first time.
Free Code Scan
Read all stored trouble codes with professional tools
Live Data Analysis
Monitor real-time sensor data to pinpoint the issue
Root Cause ID
Identify the actual problem, not just the symptom
Clear Estimate
Explain the issue and repair options with pricing
Repair & Verify
Fix the issue, clear codes, and verify the repair
Why Choose Us for Check Engine Light Repair?
Free Diagnostic Scan
Complimentary OBD-II code scan — know what you're dealing with before committing to any repairs.
ASE Certified Diagnosticians
Our technicians are ASE certified with years of diagnostic experience. We find the real problem, not just throw parts at it.
Professional-Grade Equipment
We use dealer-level scan tools with live data capabilities, freeze frame analysis, and manufacturer-specific diagnostics — far beyond a basic code reader.
Same-Day Service Available
Many check engine light repairs can be diagnosed and completed same-day, especially for common issues like sensors and ignition components.
Honest Recommendations
We explain what we find in plain language with clear options. No pressure, no upselling, no replacing parts you don't need.
All Makes & Models
From common codes on Silverados and F-150s to European vehicle diagnostics — we handle it all with manufacturer-specific expertise.
Check Engine Light On? Let's Fix It.
Don't ignore it and don't guess — get a proper diagnosis. Call us now or stop by for a free code scan.
Check Engine Light Repair Near You in Sonoma County
We serve drivers throughout Sonoma County with expert check engine light diagnostics and repair. Click your city for local service information.
Check Engine Light FAQs
Common questions about check engine light diagnosis and repair, answered by our ASE certified technicians.
How much does check engine light repair cost near me?
Check engine light repair costs vary widely depending on what triggered the light. A simple gas cap issue may just need tightening, while a catalytic converter or sensor replacement is a larger repair. We offer free diagnostic scans and provide detailed estimates before any work begins. Call (707) 584-7727 for a free diagnosis.
Can I drive with my check engine light on?
A solid (steady) check engine light usually means a non-emergency issue, but you should get it diagnosed soon to prevent further damage. A flashing check engine light is urgent — it typically indicates an engine misfire that can damage your catalytic converter. Pull over safely and call for service immediately.
What are the most common check engine light causes?
The most common causes include: loose or faulty gas cap, failing oxygen sensor, catalytic converter issues (P0420 code), mass airflow sensor problems, faulty spark plugs or ignition coils, EGR valve issues, and EVAP system leaks. Our diagnostic equipment reads the specific trouble codes to pinpoint the exact cause.
Do you offer free check engine light scans?
Yes! We offer complimentary OBD-II diagnostic scans to read your check engine light codes. Unlike auto parts stores that only read the code number, our ASE certified technicians interpret the codes in context — diagnosing the root cause, not just the symptom. This saves you from replacing parts you don't actually need.
How long does check engine light diagnosis take?
A basic OBD-II scan takes just a few minutes. Comprehensive diagnostics — where we pinpoint the exact cause and verify the fix — typically takes 30-60 minutes depending on the complexity of the issue. Many common repairs can be completed same-day once diagnosed.
Will a check engine light clear itself?
Sometimes. If the issue was temporary (like a loose gas cap), the light may turn off after several drive cycles once the problem is resolved. However, the code remains stored in your vehicle's computer. We recommend getting it scanned even if the light goes off, to confirm the issue is truly resolved and not intermittent.
What's the difference between a solid and flashing check engine light?
A solid check engine light indicates a problem that needs attention but isn't immediately dangerous — you can drive carefully to the shop. A flashing check engine light is serious and means your engine is misfiring, which can damage the catalytic converter. Reduce speed, avoid heavy acceleration, and get to a repair shop as soon as possible.
Can a check engine light affect my smog test?
Yes. In California, your vehicle will automatically fail a smog inspection if the check engine light is on. The light must be off and the OBD-II monitors must be in a 'ready' state to pass. We can diagnose and repair the issue, then verify readiness before you go for your smog check.
Do you service all vehicle makes and models?
Yes! Our ASE certified technicians diagnose and repair check engine light issues on all makes and models including domestic (Ford, Chevy, Dodge, GMC), Japanese (Toyota, Honda, Nissan, Subaru, Mazda), European (BMW, Mercedes, VW, Audi), and Korean (Hyundai, Kia) vehicles. We have professional-grade scan tools for all manufacturers.
Why is professional diagnosis better than a parts store scan?
Auto parts stores read the trouble code but can't diagnose the root cause. A P0420 code, for example, might be a bad catalytic converter, a failing oxygen sensor, an exhaust leak, or even a software issue. Our ASE certified technicians use professional-grade tools, live data analysis, and decades of experience to identify the actual problem — saving you from expensive trial-and-error part replacements.
Get Expert Check Engine Light Repair Today
Free diagnostic scan. Same-day service available. ASE certified technicians. Serving Rohnert Park and all of Sonoma County since 1989.