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.

Check soon 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

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

Diagnostic codes

Showing 1009–1032 of 1223

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U3008Control Module Ground ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU3008 concerns control module ground a. Learn what this fault indicates and where to begin diagnosis.U3009Control Module Ground BCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3009 concerns control module ground b. Learn what this fault indicates and where to begin diagnosis.U300AIgnition SwitchCheck soonNetwork & Communication45–120 minutes for initial diagnosisU300A concerns ignition switch. Learn what this fault indicates and where to begin diagnosis.U300BIgnition Input Accessory/On/StartCheck soonNetwork & Communication45–120 minutes for initial diagnosisU300B concerns ignition input accessory/on/start. Learn what this fault indicates and where to begin diagnosis.U300CIgnition Input Off/On/StartCheck soonNetwork & Communication45–120 minutes for initial diagnosisU300C concerns ignition input off/on/start. Learn what this fault indicates and where to begin diagnosis.U300DIgnition Input On/StartCheck soonNetwork & Communication45–120 minutes for initial diagnosisU300D concerns ignition input on/start. Learn what this fault indicates and where to begin diagnosis.U300EIgnition Input OnCheck soonNetwork & Communication45–120 minutes for initial diagnosisU300E concerns ignition input on. Learn what this fault indicates and where to begin diagnosis.U300FIgnition Input AccessoryCheck soonNetwork & Communication45–120 minutes for initial diagnosisU300F concerns ignition input accessory. Learn what this fault indicates and where to begin diagnosis.U3010Ignition Input StartCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3010 concerns ignition input start. Learn what this fault indicates and where to begin diagnosis.U3011Ignition Input OffCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3011 concerns ignition input off. Learn what this fault indicates and where to begin diagnosis.U3012Control Module Improper Wake-up PerformanceCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3012 concerns control module improper wake-up performance. Learn what this fault indicates and where to begin diagnosis.U3013Control Module Input Power C Circuit/OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3013 concerns control module input power c circuit/open. Learn what this fault indicates and where to begin diagnosis.U3014Control Module Input Power D Circuit/OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3014 concerns control module input power d circuit/open. Learn what this fault indicates and where to begin diagnosis.U3015Control Module Ground CCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3015 concerns control module ground c. Learn what this fault indicates and where to begin diagnosis.U3016Control Module Ground DCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3016 concerns control module ground d. Learn what this fault indicates and where to begin diagnosis.U3017Control Module Timer/Clock PerformanceCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3017 concerns control module timer/clock performance. Learn what this fault indicates and where to begin diagnosis.U3018Control Module Input Power Circuit A/B CorrelationCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3018 concerns control module input power circuit a/b correlation. Learn what this fault indicates and where to begin diagnosis.U3019Control Module Input Power Circuit B/C CorrelationCheck soonNetwork & Communication45–120 minutes for initial diagnosisU3019 concerns control module input power circuit b/c correlation. Learn what this fault indicates and where to begin diagnosis.U301AControl Module Wake-up Circuit A/OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU301A concerns control module wake-up circuit a/open. Learn what this fault indicates and where to begin diagnosis.U301BControl Module Wake-up Circuit A LowCheck soonNetwork & Communication45–120 minutes for initial diagnosisU301B concerns control module wake-up circuit a low. Learn what this fault indicates and where to begin diagnosis.U301CControl Module Wake-up Circuit A HighCheck soonNetwork & Communication45–120 minutes for initial diagnosisU301C concerns control module wake-up circuit a high. Learn what this fault indicates and where to begin diagnosis.U301DControl Module Wake-up Circuit A PerformanceCheck soonNetwork & Communication45–120 minutes for initial diagnosisU301D concerns control module wake-up circuit a performance. Learn what this fault indicates and where to begin diagnosis.U301EControl Module Wake-up Circuit B/OpenCheck soonNetwork & Communication45–120 minutes for initial diagnosisU301E concerns control module wake-up circuit b/open. Learn what this fault indicates and where to begin diagnosis.U301FControl Module Wake-up Circuit B LowCheck soonNetwork & Communication45–120 minutes for initial diagnosisU301F concerns control module wake-up circuit b low. Learn what this fault indicates and where to begin diagnosis.