Look up a trouble code — or describe the problem

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• My Fleet Manage every car you own or work on
• Trouble codes Every code, with causes and fixes
• Diagnose Describe the fault in your own words
• Fixes What actually solves a fault, and how hard it is
• VIN decoder Read the number on the windscreen
• Vehicles Models, generations and specs
• Engines Families, and the cars each was fitted to
• Transmissions Gearboxes, and what goes wrong with each
• Community Write-ups, questions and confirmed fixes
• Articles How each system works, and what goes wrong
• Browse the reference Systems, symptoms, causes, makes
• CAN bus databases Signals mirrored from opendbc

By severity

Common codes

• P0304 Cylinder 4 Misfire Detected
• P0755 Shift Solenoid B
• P0113 Intake Air Temperature Sensor 1 Circuit High Bank 1
• P0102 Mass or Volume Air Flow Sensor A Circuit Low
• P0175 System Too Rich — Bank 2
• P0457 Evaporative Emission System Leak Detected — Fuel Cap Loose or Off
• P0562 System Voltage Low
• P0087 Fuel Rail/System Pressure — Too Low Bank 1
• P0128 Coolant Thermostat — Temperature Below Regulating Point
• P0303 Cylinder 3 Misfire Detected
• U0100 Lost Communication With Engine Control Module A
• P2187 System Too Lean at Idle Bank 1
• P0351 Ignition Coil A Primary Control Circuit/Open
• P0841 Transmission Fluid Pressure Sensor/Switch A Circuit Range/Performance
• P0456 Evaporative Emission System Leak Detected — Very Small Leak
• P0172 System Too Rich — Bank 1
• P0141 O2 Sensor Heater Circuit — Bank 1 Sensor 2
• P0117 Engine Coolant Temperature Sensor 1 Circuit Low

Model pages — generations at a glance, and what owners have posted.

• Audi 19 models
• BMW 25 models
• Cadillac 20 models
• Chevrolet 44 models
• Fiat 19 models
• Ford 37 models
• Hyundai 25 models
• Kia 22 models
• Mazda 25 models
• Nissan 27 models
• Toyota 38 models
• Volkswagen 23 models

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