Diagnostic library

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9,253 diagnostic guides

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Find codes by symptomChoose what you notice to search matching code guides.

Rough idle or shakingVibration while stopped Hard to startLong cranking or no-start Engine stallsCuts out at idle or on the road Hesitates or loses powerSlow response when accelerating Battery light is onCharging system warning Harsh gear changesDelayed or rough shifting

A symptom can have several causes. Treat matching codes as clues and follow the diagnostic checks in each guide.

U · Network Clear all

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Engine1049 Emissions515 Fuel1016 Sensors & Electronics2110 Transmission866 Electrical & Charging1797 Body & Restraints193 Chassis & Brakes479 Network & Communication1228

FiltersSeverity · family

Severity

All severities9253 Low priority305 Check soon8256 Urgent621

Code family

All families9253 P · Powertrain7353 B · Body193 C · Chassis479 U · Network1228

Vehicle coverage

These are generic OBD2 definitions. Exact make, model, engine, and year compatibility will appear after vehicle-fitment data is added.

Diagnostic codes

Showing 1–24 of 1228

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U0001High Speed CAN Communication BusCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0001 means High Speed CAN Communication Bus. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.U0100Lost Communication With ECM/PCM AUrgentNetwork & Communication1–3 hours for initial diagnosisU0100 means Lost Communication With ECM/PCM A. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.U0101Lost Communication With Transmission Control ModuleUrgentNetwork & Communication1–3 hours for initial diagnosisU0101 means Lost Communication With Transmission Control Module. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.U0121Lost Communication With Anti-Lock Brake System Control ModuleUrgentNetwork & Communication1–3 hours for initial diagnosisU0121 means Lost Communication With Anti-Lock Brake System Control Module. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.U0140Lost Communication With Body Control ModuleCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0140 means Lost Communication With Body Control Module. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.U0010Medium Speed CAN Communication BusCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0010 concerns medium speed can communication bus. Learn what this fault indicates and where to begin diagnosis.U0011Medium Speed CAN Communication Bus PerformanceCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0011 concerns medium speed can communication bus performance. Learn what this fault indicates and where to begin diagnosis.U0012Medium Speed CAN Communication Bus (+) OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0012 concerns medium speed can communication bus (+) open. Learn what this fault indicates and where to begin diagnosis.U0013Medium Speed CAN Communication Bus (+) LowCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0013 concerns medium speed can communication bus (+) low. Learn what this fault indicates and where to begin diagnosis.U0014Medium Speed CAN Communication Bus (+) HighCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0014 concerns medium speed can communication bus (+) high. Learn what this fault indicates and where to begin diagnosis.U0015Medium Speed CAN Communication Bus (-) OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0015 concerns medium speed can communication bus (-) open. Learn what this fault indicates and where to begin diagnosis.U0016Medium Speed CAN Communication Bus (-) LowCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0016 concerns medium speed can communication bus (-) low. Learn what this fault indicates and where to begin diagnosis.U0017Medium Speed CAN Communication Bus (-) HighCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0017 concerns medium speed can communication bus (-) high. Learn what this fault indicates and where to begin diagnosis.U0018Medium Speed CAN Communication Bus (-) shorted to Bus (+)Check soonNetwork & Communication45–120 minutes for initial diagnosisU0018 concerns medium speed can communication bus (-) shorted to bus (+). Learn what this fault indicates and where to begin diagnosis.U0019Low Speed CAN Communication BusCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0019 concerns low speed can communication bus. Learn what this fault indicates and where to begin diagnosis.U0020Low Speed CAN Communication Bus PerformanceCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0020 concerns low speed can communication bus performance. Learn what this fault indicates and where to begin diagnosis.U0021Low Speed CAN Communication Bus (+) OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0021 concerns low speed can communication bus (+) open. Learn what this fault indicates and where to begin diagnosis.U0022Low Speed CAN Communication Bus (+) LowCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0022 concerns low speed can communication bus (+) low. Learn what this fault indicates and where to begin diagnosis.U0023Low Speed CAN Communication Bus (+) HighCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0023 concerns low speed can communication bus (+) high. Learn what this fault indicates and where to begin diagnosis.U0024Low Speed CAN Communication Bus (-) OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0024 concerns low speed can communication bus (-) open. Learn what this fault indicates and where to begin diagnosis.U0025Low Speed CAN Communication Bus (-) LowCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0025 concerns low speed can communication bus (-) low. Learn what this fault indicates and where to begin diagnosis.U0026Low Speed CAN Communication Bus (-) HighCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0026 concerns low speed can communication bus (-) high. Learn what this fault indicates and where to begin diagnosis.U0027Low Speed CAN Communication Bus (-) shorted to Bus (+)Check soonNetwork & Communication45–120 minutes for initial diagnosisU0027 concerns low speed can communication bus (-) shorted to bus (+). Learn what this fault indicates and where to begin diagnosis.U0028Vehicle Communication Bus ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU0028 concerns vehicle communication bus a. Learn what this fault indicates and where to begin diagnosis.