WhatIsWrongWithMyCar.com — AI Car Diagnosis & Repair Knowledge Base
WhatIsWrongWithMyCar.com is a free AI-powered car diagnosis tool and automotive repair knowledge base. Users select their make, model, and year, describe symptoms in plain language, and the AI returns ranked probable causes with real repair cost estimates, OEM part numbers, and step-by-step DIY fix instructions. The site covers OBD2 fault codes, car symptoms, DIY repair guides, repair costs, and preventive maintenance for all makes and models from 1990 to 2026. Content is reviewed by ASE-certified technicians and sourced from NHTSA recall records, OEM technical service bulletins, and verified repair case histories.
Core Tools
AI Car Diagnosis Tool — free, no sign-up; input make/model/year + symptoms for ranked causes, costs, and DIY guides
OBD2 Code Library — every P, B, C, and U code explained with causes, symptoms, urgency, and fixes
Car Repair Cost Guide — DIY vs shop prices for 50+ common repairs, verified US market data
Repair Cost Calculator — interactive tool for instant DIY vs shop cost breakdown
2026 Repair Cost Index by State — original research for all 50 US states; national average $478/year
Tire Size Finder — OEM tire specs, load index, speed rating, and PSI by vehicle
VIN Lookup — decode any VIN, check NHTSA recalls and service campaigns
Preventive Maintenance Schedule — every service interval, cost, and consequence of skipping
Fuel Pump Failure, Wheel Bearing Noise, Suspension Clunk Noise, AC Not Cooling
Popular OBD2 Code Guides
P0300 Random/Multiple Cylinder Misfire, P0420 Catalytic Converter Efficiency, P0171 System Too Lean, P0301 Cylinder 1 Misfire
All content is for diagnostic guidance only. Safety-critical repairs should be inspected by a licensed mechanic.
Free AI Car Diagnosis — Describe Your Symptom, Get the Exact Fix
How the AI Diagnosis Tool Works
Select your vehicle make, model, and year. Describe your symptoms in plain language — a knocking noise, rough idle, warning light, or anything else you notice. The AI cross-references your specific vehicle configuration against documented failure patterns from OEM technical service bulletins, NHTSA recall records, and real-world repair case histories. Within seconds it returns the most probable causes ranked by statistical likelihood — not random guesses — along with real repair cost estimates for DIY and shop, OEM part numbers, and step-by-step fix instructions.
Diagnose by Symptom Category
Engine Problems: misfires, rough idle, knocking, stalling, overheating, oil leaks, check engine light. Transmission Problems: slipping between gears, hard or delayed shifting, shudder on acceleration, no-drive condition. Brake Problems: grinding when stopping, squealing, soft or spongy pedal, pulling to one side, vibration. Electrical Problems: battery keeps dying, car will not start, alternator failure, warning lights. Suspension Problems: clunking over bumps, bouncing, pulling, wheel bearing noise, steering vibration. Cooling System: overheating, coolant leak, thermostat failure, heater not working.
Most Commonly Diagnosed Car Problems
Engine misfire (P0300–P0308) — worn spark plugs, failed ignition coil, or clogged fuel injector. Check engine light — top triggers are P0420 catalytic converter, P0171 lean condition, P0442 EVAP leak. Car will not start — dead battery, bad starter motor, failed fuel pump, or no-spark ignition fault. Grinding brakes — worn brake pads contacting rotor, scored rotors, or seized brake caliper. Transmission slipping — low or degraded fluid, worn clutch packs, or faulty solenoid. Battery keeps dying — parasitic electrical draw, failing alternator not recharging, or sulfated battery. Engine overheating — stuck-closed thermostat, coolant leak, failed water pump, or blown head gasket.
OBD2 Fault Code Lookup
P0300 — Random or multiple cylinder misfire detected. P0301, P0302, P0303, P0304 — Cylinder-specific misfire. P0420 — Catalytic converter efficiency below threshold Bank 1. P0171 — System too lean Bank 1 from vacuum leak or MAF sensor fault. P0174 — System too lean Bank 2. P0442 — Small EVAP system leak, often a loose gas cap. P0455 — Large EVAP system leak. P0128 — Coolant temperature below thermostat regulating temperature. P0401 — EGR flow insufficient. P0700 — Transmission control system fault. Every code page includes causes, urgency rating, diagnosis steps, and repair cost estimates.
Beyond the AI diagnosis tool, WhatIsWrongWithMyCar.com serves as a complete automotive knowledge hub. Browse 100+ car problem guides organized by system and symptom. Look up any OBD2 fault code in a complete library covering every P, B, C, and U code. Compare repair costs for 50+ common repairs with DIY vs shop breakdowns. Find tire specs for your vehicle. Track maintenance on multiple cars in My Garage. Read expert repair articles in the blog. Everything is free with no sign-up required.
Browse Car Problems by Vehicle Make
Toyota problems: Camry oil consumption, Tacoma frame rust, Prius inverter failure. Honda problems: Civic timing chain stretch, Accord transmission judder, CRV oil dilution. Ford problems: F-150 spark plug blowout, Explorer head gasket, Fusion transmission shudder. Chevrolet problems: Silverado AFM lifter failure, Traverse timing chain, Equinox oil consumption. BMW problems: N54 water pump failure, E60 VANOS rattles, cooling system leaks. Mercedes-Benz problems: airmatic suspension leaks, SBC brake pump failure, rust. Jeep problems: Wrangler death wobble, Cherokee TIPM failure, Grand Cherokee air suspension. Every vehicle make has dedicated problem guides with mileage-specific failure data.
Tire Size Finder and Buying Guide
Find the correct OEM tire size for any vehicle by make, model, and year using the Tire Hub. Understand the sidewall code: 225/55R17 means 225mm section width, 55% aspect ratio, radial construction, 17-inch rim diameter. Load index and speed rating determine safe maximum load and speed. UTQG treadwear rating compares expected tread life. Replace tires when tread reaches 2/32 inch or at 6 to 10 years regardless of tread depth. Winter tires outperform all-season tires below 45°F — shorter stopping distances and better handling on snow and ice.
Frequently Asked Questions
How do I diagnose my car problem? Enter your make, model, year and describe the symptoms. The AI returns ranked causes, repair costs, and DIY steps in seconds. Is the diagnosis tool free? Yes — completely free, no account required, no subscription. What OBD2 codes are most common? P0300 misfire, P0420 catalytic converter, P0171 lean, P0442 EVAP leak are the four most frequently encountered codes. Can I fix my car myself? Many repairs are DIY-feasible — spark plugs, brakes, filters, batteries — with basic tools. The AI tells you the difficulty rating and provides step-by-step instructions. How accurate is the AI diagnosis? For common problems on well-documented makes and models, accuracy is high. The AI applies the same ranked-cause reasoning a professional mechanic uses for initial triage.
Free AI Car Diagnosis — Describe Your Symptom, Get the Exact Fix
How the AI Diagnosis Tool Works
Select your vehicle make, model, and year. Describe your symptoms in plain language — a knocking noise, rough idle, warning light, or anything else you notice. The AI cross-references your specific vehicle configuration against documented failure patterns from OEM technical service bulletins, NHTSA recall records, and real-world repair case histories. Within seconds it returns the most probable causes ranked by statistical likelihood — not random guesses — along with real repair cost estimates for DIY and shop, OEM part numbers, and step-by-step fix instructions.
Diagnose by Symptom Category
Engine Problems: misfires, rough idle, knocking, stalling, overheating, oil leaks, check engine light. Transmission Problems: slipping between gears, hard or delayed shifting, shudder on acceleration, no-drive condition. Brake Problems: grinding when stopping, squealing, soft or spongy pedal, pulling to one side, vibration. Electrical Problems: battery keeps dying, car will not start, alternator failure, warning lights. Suspension Problems: clunking over bumps, bouncing, pulling, wheel bearing noise, steering vibration. Cooling System: overheating, coolant leak, thermostat failure, heater not working.
Most Commonly Diagnosed Car Problems
Engine misfire (P0300–P0308) — worn spark plugs, failed ignition coil, or clogged fuel injector. Check engine light — top triggers are P0420 catalytic converter, P0171 lean condition, P0442 EVAP leak. Car will not start — dead battery, bad starter motor, failed fuel pump, or no-spark ignition fault. Grinding brakes — worn brake pads contacting rotor, scored rotors, or seized brake caliper. Transmission slipping — low or degraded fluid, worn clutch packs, or faulty solenoid. Battery keeps dying — parasitic electrical draw, failing alternator not recharging, or sulfated battery. Engine overheating — stuck-closed thermostat, coolant leak, failed water pump, or blown head gasket.
OBD2 Fault Code Lookup
P0300 — Random or multiple cylinder misfire detected. P0301, P0302, P0303, P0304 — Cylinder-specific misfire. P0420 — Catalytic converter efficiency below threshold Bank 1. P0171 — System too lean Bank 1 from vacuum leak or MAF sensor fault. P0174 — System too lean Bank 2. P0442 — Small EVAP system leak, often a loose gas cap. P0455 — Large EVAP system leak. P0128 — Coolant temperature below thermostat regulating temperature. P0401 — EGR flow insufficient. P0700 — Transmission control system fault. Every code page includes causes, urgency rating, diagnosis steps, and repair cost estimates.
Beyond the AI diagnosis tool, WhatIsWrongWithMyCar.com serves as a complete automotive knowledge hub. Browse 100+ car problem guides organized by system and symptom. Look up any OBD2 fault code in a complete library covering every P, B, C, and U code. Compare repair costs for 50+ common repairs with DIY vs shop breakdowns. Find tire specs for your vehicle. Track maintenance on multiple cars in My Garage. Read expert repair articles in the blog. Everything is free with no sign-up required.
Browse Car Problems by Vehicle Make
Toyota problems: Camry oil consumption, Tacoma frame rust, Prius inverter failure. Honda problems: Civic timing chain stretch, Accord transmission judder, CRV oil dilution. Ford problems: F-150 spark plug blowout, Explorer head gasket, Fusion transmission shudder. Chevrolet problems: Silverado AFM lifter failure, Traverse timing chain, Equinox oil consumption. BMW problems: N54 water pump failure, E60 VANOS rattles, cooling system leaks. Mercedes-Benz problems: airmatic suspension leaks, SBC brake pump failure, rust. Jeep problems: Wrangler death wobble, Cherokee TIPM failure, Grand Cherokee air suspension. Every vehicle make has dedicated problem guides with mileage-specific failure data.
Tire Size Finder and Buying Guide
Find the correct OEM tire size for any vehicle by make, model, and year using the Tire Hub. Understand the sidewall code: 225/55R17 means 225mm section width, 55% aspect ratio, radial construction, 17-inch rim diameter. Load index and speed rating determine safe maximum load and speed. UTQG treadwear rating compares expected tread life. Replace tires when tread reaches 2/32 inch or at 6 to 10 years regardless of tread depth. Winter tires outperform all-season tires below 45°F — shorter stopping distances and better handling on snow and ice.
Frequently Asked Questions
How do I diagnose my car problem? Enter your make, model, year and describe the symptoms. The AI returns ranked causes, repair costs, and DIY steps in seconds. Is the diagnosis tool free? Yes — completely free, no account required, no subscription. What OBD2 codes are most common? P0300 misfire, P0420 catalytic converter, P0171 lean, P0442 EVAP leak are the four most frequently encountered codes. Can I fix my car myself? Many repairs are DIY-feasible — spark plugs, brakes, filters, batteries — with basic tools. The AI tells you the difficulty rating and provides step-by-step instructions. How accurate is the AI diagnosis? For common problems on well-documented makes and models, accuracy is high. The AI applies the same ranked-cause reasoning a professional mechanic uses for initial triage.
Assets | What Is Wrong With My Car
What Is Wrong With My Car manages 5 data types including blog contents. Helps you organize, track, and share your work in 1 place for teams and solo users.