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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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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 385–408 of 2110

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P0500Vehicle Speed Sensor A MalfunctionSensors & ElectronicsDiagnose P0500 vehicle speed sensor code. Learn how the VSS works and how to fix speedometer and shift issues.P0501Vehicle Speed Sensor A Range/PerformanceCheck soonSensors & Electronics45–120 minutes for initial diagnosisP0501 means Vehicle Speed Sensor A Range/Performance. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0504Brake Switch A/B CorrelationCheck soonSensors & Electronics30–90 minutes for initial diagnosisP0504 means the brake-pedal switch signals disagree when the control module expects them to match. Learn what to check before replacing parts.P050ACold Start Idle Control System PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP050A relates to cold start idle control system performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P050DCold Start Rough IdleCheck soonSensors & Electronics30–120 minutes for initial diagnosisP050D relates to cold start rough idle. Check the fault conditions and vehicle-specific procedure before replacing parts.P050ECold Start Engine Exhaust Temperature Too LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP050E relates to cold start engine exhaust temperature too low. Check the fault conditions and vehicle-specific procedure before replacing parts.P050FBrake Assist Vacuum Too LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP050F relates to brake assist vacuum too low. Check the fault conditions and vehicle-specific procedure before replacing parts.P0510Closed Throttle Position Switch MalfunctionCheck soonSensors & Electronics30–120 minutes for initial diagnosisP0510 indicates a fault related to closed throttle position switch malfunction. Learn the likely causes and a practical diagnostic order before replacing parts.P0518Idle Air Control Circuit IntermittentCheck soonSensors & Electronics30–120 minutes for initial diagnosisP0518 relates to idle air control circuit intermittent. Check the fault conditions and vehicle-specific procedure before replacing parts.P0519Idle Air Control System PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP0519 relates to idle air control system performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P051ACrankcase Pressure Sensor A CircuitCheck soonSensors & Electronics30–120 minutes for initial diagnosisP051A relates to crankcase pressure sensor a circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P051BCrankcase Pressure Sensor A Circuit Range/PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP051B relates to crankcase pressure sensor a circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P051CCrankcase Pressure Sensor A Circuit LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP051C relates to crankcase pressure sensor a circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P051DCrankcase Pressure Sensor A Circuit HighCheck soonSensors & Electronics30–120 minutes for initial diagnosisP051D relates to crankcase pressure sensor a circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P051ECrankcase Pressure Sensor A Circuit Intermittent/ErraticCheck soonSensors & Electronics30–120 minutes for initial diagnosisP051E relates to crankcase pressure sensor a circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P051FPCV Filter RestrictionCheck soonSensors & Electronics30–120 minutes for initial diagnosisP051F relates to pcv filter restriction. Check the fault conditions and vehicle-specific procedure before replacing parts.P0525Cruise Control Servo Control Circuit Range/PerformanceLow prioritySensors & Electronics30–120 minutes for initial diagnosisP0525 relates to cruise control servo control circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P052EPCV Regulator Valve PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP052E relates to pcv regulator valve performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P0530A/C Refrigerant Pressure Sensor CircuitLow prioritySensors & Electronics30–120 minutes for initial diagnosisP0530 indicates a fault related to a/c refrigerant pressure sensor circuit. Learn the likely causes and a practical diagnostic order before replacing parts.P0531A/C Refrigerant Pressure Sensor Range/PerformanceLow prioritySensors & Electronics30–120 minutes for initial diagnosisP0531 indicates a fault related to a/c refrigerant pressure sensor range/performance. Learn the likely causes and a practical diagnostic order before replacing parts.P0532A/C Refrigerant Pressure Sensor Circuit LowLow prioritySensors & Electronics30–120 minutes for initial diagnosisP0532 indicates a fault related to a/c refrigerant pressure sensor circuit low. Learn the likely causes and a practical diagnostic order before replacing parts.P0533A/C Refrigerant Pressure Sensor Circuit HighLow prioritySensors & Electronics30–120 minutes for initial diagnosisP0533 indicates a fault related to a/c refrigerant pressure sensor circuit high. Learn the likely causes and a practical diagnostic order before replacing parts.P0534Air Conditioner Refrigerant Charge LossLow prioritySensors & Electronics30–120 minutes for initial diagnosisP0534 indicates a fault related to air conditioner refrigerant charge loss. Learn the likely causes and a practical diagnostic order before replacing parts.P053APCV Heater A Control Circuit /OpenCheck soonSensors & Electronics30–120 minutes for initial diagnosisP053A relates to pcv heater a control circuit /open. Check the fault conditions and vehicle-specific procedure before replacing parts.