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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

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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 289–305 of 305

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P0139Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0139 means Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0151Oxygen Sensor Circuit Low Voltage Bank 2 Sensor 1Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0151 means Oxygen Sensor Circuit Low Voltage Bank 2 Sensor 1. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0152Oxygen Sensor Circuit High Voltage Bank 2 Sensor 1Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0152 means Oxygen Sensor Circuit High Voltage Bank 2 Sensor 1. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0153Oxygen Sensor Circuit Slow Response Bank 2 Sensor 1Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0153 means Oxygen Sensor Circuit Slow Response Bank 2 Sensor 1. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0154Oxygen Sensor Circuit No Activity Detected Bank 2 Sensor 1Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0154 means Oxygen Sensor Circuit No Activity Detected Bank 2 Sensor 1. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0155Oxygen Sensor Heater Circuit Bank 2 Sensor 1Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0155 means Oxygen Sensor Heater Circuit Bank 2 Sensor 1. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0156Oxygen Sensor Circuit Bank 2 Sensor 2Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0156 means Oxygen Sensor Circuit Bank 2 Sensor 2. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0157Oxygen Sensor Circuit Low Voltage Bank 2 Sensor 2Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0157 means Oxygen Sensor Circuit Low Voltage Bank 2 Sensor 2. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0158Oxygen Sensor Circuit High Voltage Bank 2 Sensor 2Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0158 means Oxygen Sensor Circuit High Voltage Bank 2 Sensor 2. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0161Oxygen Sensor Heater Circuit Bank 2 Sensor 2Low prioritySensors & Electronics30–90 minutes for initial diagnosisP0161 means Oxygen Sensor Heater Circuit Bank 2 Sensor 2. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0403Exhaust Gas Recirculation Control Circuit MalfunctionLow priorityEmissions System30–90 minutes for initial diagnosisP0403 means Exhaust Gas Recirculation Control Circuit Malfunction. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0404Exhaust Gas Recirculation Control Circuit Range/PerformanceLow priorityEmissions System30–90 minutes for initial diagnosisP0404 means Exhaust Gas Recirculation Control Circuit Range/Performance. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0405Exhaust Gas Recirculation Sensor A Circuit LowLow priorityEmissions System30–90 minutes for initial diagnosisP0405 means Exhaust Gas Recirculation Sensor A Circuit Low. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0406Exhaust Gas Recirculation Sensor A Circuit HighLow priorityEmissions System30–90 minutes for initial diagnosisP0406 means Exhaust Gas Recirculation Sensor A Circuit High. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0412Secondary Air Injection System Switching Valve A Circuit MalfunctionLow priorityEmissions System30–90 minutes for initial diagnosisP0412 means Secondary Air Injection System Switching Valve A Circuit Malfunction. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0413Secondary Air Injection System Switching Valve A Circuit OpenLow priorityEmissions System30–90 minutes for initial diagnosisP0413 means Secondary Air Injection System Switching Valve A Circuit Open. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.P0414Secondary Air Injection System Switching Valve A Circuit ShortedLow priorityEmissions System30–90 minutes for initial diagnosisP0414 means Secondary Air Injection System Switching Valve A Circuit Shorted. Learn the likely symptoms, common causes, and a safe diagnostic order before replacing parts.