✅ Written by ASE-Certified Mechanics

Check Engine Light On?
We Know Exactly Why.

Expert OBD-II repair guides for your exact vehicle — with real symptoms, root causes, and step-by-step DIY fixes.

Popular: P0300 · P0171 · P0420 · P0455

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🔧 22+ Years Experience

🚗 10 Major US Makes

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500+ DTC Repair Guides

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10 Top US Vehicle Makes

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ASE Certified Technicians

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Save $$$ vs. Dealership Diagnosis

Browse by Vehicle Make

Select your make to see all DTC codes and repair guides for your vehicle.

ChevroletSilverado, Equinox, Tahoe…

FordF-150, Explorer, Escape…

ToyotaCamry, RAV4, Tacoma…

HondaCivic, CR-V, Accord…

Ram1500, 2500, ProMaster…

GMCSierra, Terrain, Yukon…

JeepWrangler, Cherokee, Gladiator…

HyundaiElantra, Tucson, Santa Fe…

KiaSorento, Sportage, Soul…

NissanAltima, Rogue, Frontier…

Most Common OBD-II Codes

The top check-engine codes US drivers deal with — click for the full repair guide.

Random/Multiple Cylinder Misfire Rough idle, stuttering, possible AFM lifter failure

System Too Lean (Bank 1) MAF sensor, vacuum leak, fuel pressure issue

Catalyst System Efficiency Below Threshold O2 sensor, catalytic converter, exhaust leak

EVAP System Large Leak Detected Loose gas cap, purge valve, EVAP canister

Coolant Temp Below Thermostat Regulating Temp Stuck-open thermostat, temp sensor fault

Transmission Control System Malfunction TCM fault, transmission solenoid, fluid issue

Camshaft Position Actuator Circuit (Bank 1) OCV solenoid, dirty oil, cam phaser wear

Oil Pressure Sensor Range / Performance Oil pressure sensor, low oil, oil pump

How FixAutoCar.pro Works

From check engine light to fix — in three steps.

1

Find Your Code

Enter your OBD-II code (P0300, C0035, etc.) in the search bar, or browse by your vehicle make. Every guide is matched to your exact engine.

2

Read the Expert Guide

Each article is written by an ASE-certified mechanic with 10–24 years of real shop experience. Get symptoms, root causes, and a step-by-step diagnostic process.

3

Fix It Yourself or Know What to Expect

Get the exact parts and tools you need. Know the real DIY cost vs. shop cost — and when a job truly needs a professional.