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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 1–24 of 9253

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B0001Driver Frontal Stage 1 Deployment ControlUrgentBody & Restraints1–3 hours for initial diagnosisB0001 means Driver Frontal Stage 1 Deployment Control. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.B0002Driver Frontal Stage 2 Deployment ControlUrgentBody & Restraints1–3 hours for initial diagnosisB0002 means Driver Frontal Stage 2 Deployment Control. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.C0035Left Front Wheel Speed SensorCheck soonChassis & Brakes45–120 minutes for initial diagnosisC0035 means Left Front Wheel Speed Sensor. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.C0040Right Front Wheel Speed SensorCheck soonChassis & Brakes45–120 minutes for initial diagnosisC0040 means Right Front Wheel Speed Sensor. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.C0045Left Rear Wheel Speed SensorCheck soonChassis & Brakes45–120 minutes for initial diagnosisC0045 means Left Rear Wheel Speed Sensor. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.C0050Right Rear Wheel Speed SensorCheck soonChassis & Brakes45–120 minutes for initial diagnosisC0050 means Right Rear Wheel Speed Sensor. Review likely symptoms, causes, safety considerations, and a sensible diagnostic order.P0051Heated Oxygen Sensor Heater Control Circuit Low Bank 2 Sensor 1Low prioritySensors & Electronics45–120 minutes for initial diagnosisP0051 means Heated Oxygen Sensor Heater Control Circuit Low Bank 2 Sensor 1. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0057Heated Oxygen Sensor Heater Control Circuit Low Bank 2 Sensor 2Low prioritySensors & Electronics45–120 minutes for initial diagnosisP0057 means Heated Oxygen Sensor Heater Control Circuit Low Bank 2 Sensor 2. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0069Manifold Absolute Pressure–Barometric Pressure CorrelationCheck soonSensors & Electronics45–120 minutes for initial diagnosisP0069 means Manifold Absolute Pressure–Barometric Pressure Correlation. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0089Fuel Pressure Regulator 1 PerformanceCheck soonFuel System45–120 minutes for initial diagnosisP0089 means Fuel Pressure Regulator 1 Performance. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0093Fuel System Leak Detected — Large LeakUrgentFuel System1–3 hours for initial diagnosisP0093 means Fuel System Leak Detected — Large Leak. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0128Coolant Thermostat Below Regulating TemperatureCheck soonEngine Problems30–75 minutesDiagnose P0128 thermostat code. Learn why your engine isn't reaching operating temperature.P0130O2 Sensor Circuit Malfunction Bank 1 Sensor 1Sensors & ElectronicsFix P0130 oxygen sensor code. Learn about O2 sensor locations, testing procedures, and replacement tips for Bank 1 Sensor 1.P0171System Too Lean Bank 1 - Complete GuideCheck soonFuel System45–120 minutesDiagnose and fix P0171 system too lean code. Understand what causes a lean fuel mixture and how to solve it with our comprehensive guide.P0172System Too Rich Bank 1 - Causes & SolutionsFuel SystemDiagnose P0172 rich fuel mixture code. Learn what causes excess fuel in the air-fuel mixture and how to fix it.P0217Engine Overtemperature ConditionUrgentEngine Problems1–3 hours for initial diagnosisP0217 means Engine Overtemperature Condition. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0218Transmission Fluid Overtemperature ConditionUrgentTransmission Issues1–3 hours for initial diagnosisP0218 means Transmission Fluid Overtemperature Condition. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0221Throttle/Pedal Position Sensor/Switch B Circuit Range/PerformanceCheck soonSensors & Electronics45–120 minutes for initial diagnosisP0221 means Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0235Turbocharger/Supercharger Boost Sensor A CircuitCheck soonSensors & Electronics45–120 minutes for initial diagnosisP0235 means Turbocharger/Supercharger Boost Sensor A Circuit. Learn the likely symptoms, causes, safety implications, and a practical diagnostic order.P0304Cylinder 4 Misfire Detected - Causes & FixesUrgentEngine Problems30–75 minutesLearn what P0304 means, why cylinder 4 is misfiring, and how to fix it. Complete guide with symptoms, causes, and step-by-step solutions.P0335Crankshaft Position Sensor Circuit MalfunctionSensors & ElectronicsDiagnose P0335 crank sensor code. Learn about the crankshaft position sensor and no-start conditions.P0340Camshaft Position Sensor Circuit MalfunctionSensors & ElectronicsFix P0340 camshaft sensor code. Learn about cam position sensor function and replacement.P0420Catalyst System Efficiency Below ThresholdLow priorityEmissions System60–150 minutesDiagnose P0420 catalyst efficiency below threshold on Bank 1. Learn what O2 sensor data can show and what to check before replacing the catalytic converter.P0442EVAP System Small Leak DetectedLow priorityEmissions System30–120 minutesFix P0442 evaporative emission system leak. Learn common causes of small EVAP leaks and how to find them.