Car Problem Diagnosis Hub: Find Any Car Problem by System, Symptom, or Code
How to Use This Diagnosis Hub
Start with the vehicle system producing the problem — engine, transmission, brakes, electrical, cooling, or suspension. Each system category links to individual problem pages that cover root causes ranked by probability, the specific OBD2 fault codes associated with each failure mode, a step-by-step diagnostic procedure you can follow with basic tools, and realistic repair cost estimates for both do-it-yourself and professional shop repair. For a vehicle-specific result based on your exact make, model, year, and symptom description, use the free AI diagnosis tool at the top of this page.
Engine Problems
Engine misfire with codes P0300–P0308. Check engine light steady or flashing. Rough idle from vacuum leak, MAF sensor, or spark plugs. Engine overheating from thermostat failure or coolant loss. Oil leaks from gaskets and seals. Stalling under load or at idle. Low oil pressure. Each guide covers ranked causes, diagnosis steps, and cost to repair for DIY and shop.
Brake, Transmission, and Electrical Problems
Grinding brakes from worn pads, scored rotors, or seized calipers. Soft brake pedal from air in lines or failing master cylinder. Transmission slipping or delayed engagement. Hard shifting or shudder on acceleration. Battery dies repeatedly from parasitic draw or failing alternator. Car that will not start — covers battery, starter motor, fuel pump, and ignition system failures.