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

• P2187 System Too Lean at Idle Bank 1
• P0016 Crankshaft Position — Camshaft Position Correlation (Bank 1 Sensor A)
• P0201 Cylinder 1 Injector A Circuit
• P2002 Particulate Filter Efficiency Below Threshold — Bank 1
• P0440 Evaporative Emission System Malfunction
• P0017 Crankshaft Position — Camshaft Position Correlation (Bank 1 Sensor B)
• P0303 Cylinder 3 Misfire Detected
• U0100 Lost Communication With Engine Control Module A
• P0304 Cylinder 4 Misfire Detected
• P0457 Evaporative Emission System Leak Detected — Fuel Cap Loose or Off
• P0118 Engine Coolant Temperature Sensor 1 Circuit High
• P0449 Evaporative Emission System Vent Valve/Solenoid Circuit
• P0506 Idle Air Control System RPM Lower Than Expected
• P2096 Post Catalyst Fuel Trim System Too Lean — Bank 1
• P0305 Cylinder 5 Misfire Detected
• P0138 O2 Sensor Circuit High Voltage — Bank 1 Sensor 2
• P0420 Catalyst System Efficiency Below Threshold — Bank 1
• P0135 O2 Sensor Heater Circuit — Bank 1 Sensor 1

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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