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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.

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

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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 889–912 of 1223

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U0631Lost Communication With Engine Coolant Temperature Sensor 5Check soonNetwork & Communication45–120 minutes for initial diagnosisU0631 concerns lost communication with engine coolant temperature sensor 5. Learn what this fault indicates and where to begin diagnosis.U0632Lost Communication With Fan 1Check soonNetwork & Communication45–120 minutes for initial diagnosisU0632 concerns lost communication with fan 1. Learn what this fault indicates and where to begin diagnosis.U0633Lost Communication With Fan 2Check soonNetwork & Communication45–120 minutes for initial diagnosisU0633 concerns lost communication with fan 2. Learn what this fault indicates and where to begin diagnosis.U0634Lost Communication With Hybrid/EV Battery Pack Coolant Temperature Sensor ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU0634 concerns lost communication with hybrid/ev battery pack coolant temperature sensor a. Learn what this fault indicates and where to begin diagnosis.U0635Lost Communication With Hybrid/EV Battery Pack Coolant Temperature Sensor BCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0635 concerns lost communication with hybrid/ev battery pack coolant temperature sensor b. Learn what this fault indicates and where to begin diagnosis.U0636Lost Communication With Hybrid/EV Battery Pack Coolant Control Valve ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU0636 concerns lost communication with hybrid/ev battery pack coolant control valve a. Learn what this fault indicates and where to begin diagnosis.U0637Lost Communication With Hybrid/EV Battery Pack Coolant Control Valve BCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0637 concerns lost communication with hybrid/ev battery pack coolant control valve b. Learn what this fault indicates and where to begin diagnosis.U0638Lost Communication With Hybrid/EV Electronics Coolant Temperature Sensor ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU0638 concerns lost communication with hybrid/ev electronics coolant temperature sensor a. Learn what this fault indicates and where to begin diagnosis.U0639Lost Communication With Hybrid/EV Electronics Coolant Temperature Sensor BCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0639 concerns lost communication with hybrid/ev electronics coolant temperature sensor b. Learn what this fault indicates and where to begin diagnosis.U063ALost Communication With Hybrid/EV Electronics Coolant Temperature Sensor CCheck soonNetwork & Communication45–120 minutes for initial diagnosisU063A concerns lost communication with hybrid/ev electronics coolant temperature sensor c. Learn what this fault indicates and where to begin diagnosis.U063BLost Communication With Coolant Bypass Valve Actuator ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU063B concerns lost communication with coolant bypass valve actuator a. Learn what this fault indicates and where to begin diagnosis.U063CLost Communication With Coolant Bypass Valve Actuator BCheck soonNetwork & Communication45–120 minutes for initial diagnosisU063C concerns lost communication with coolant bypass valve actuator b. Learn what this fault indicates and where to begin diagnosis.U063DLost Communication With Hybrid/EV Electronics Coolant Pump ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU063D concerns lost communication with hybrid/ev electronics coolant pump a. Learn what this fault indicates and where to begin diagnosis.U063ELost Communication With Exhaust Heat Exchanger Bypass Valve Actuator ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU063E concerns lost communication with exhaust heat exchanger bypass valve actuator a. Learn what this fault indicates and where to begin diagnosis.U063FLost Communication With Engine Coolant Flow Control Valve Position SensorCheck soonNetwork & Communication45–120 minutes for initial diagnosisU063F concerns lost communication with engine coolant flow control valve position sensor. Learn what this fault indicates and where to begin diagnosis.U0640Lost Communication With EVAP Fuel Vapor Temperature Sensor CircuitCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0640 concerns lost communication with evap fuel vapor temperature sensor circuit. Learn what this fault indicates and where to begin diagnosis.U0641Lost Communication With EVAP System Pressure Sensor/Switch Circuit ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU0641 concerns lost communication with evap system pressure sensor/switch circuit a. Learn what this fault indicates and where to begin diagnosis.U0642Lost Communication With EVAP System Pressure Sensor/Switch Circuit BCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0642 concerns lost communication with evap system pressure sensor/switch circuit b. Learn what this fault indicates and where to begin diagnosis.U0643Lost Communication With Turbocharger/Supercharger A Temperature SensorCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0643 concerns lost communication with turbocharger/supercharger a temperature sensor. Learn what this fault indicates and where to begin diagnosis.U0644Lost Communication With Wastegate Position Sensor ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU0644 concerns lost communication with wastegate position sensor a. Learn what this fault indicates and where to begin diagnosis.U0645Lost Communication With Active Air Dam ModuleCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0645 concerns lost communication with active air dam module. Learn what this fault indicates and where to begin diagnosis.U0646Lost Communication With Motor Electronics Coolant Pump ACheck soonNetwork & Communication45–120 minutes for initial diagnosisU0646 concerns lost communication with motor electronics coolant pump a. Learn what this fault indicates and where to begin diagnosis.U0647Lost Communication With Motor Electronics Coolant Pump BCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0647 concerns lost communication with motor electronics coolant pump b. Learn what this fault indicates and where to begin diagnosis.U0648Lost Communication With Motor Electronics Coolant Pump CCheck soonNetwork & Communication45–120 minutes for initial diagnosisU0648 concerns lost communication with motor electronics coolant pump c. Learn what this fault indicates and where to begin diagnosis.