Diagnostic library

Find an OBD2 code

Search the code from your scanner, then narrow the library by system, severity, or code family.

9,253 diagnostic guides

Sort

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.

Emissions System Clear all

Quick browse

Choose a vehicle system

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

Vehicle coverage

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

Diagnostic codes

Showing 73–96 of 515

Most searched first

P0459EVAP System Purge Control Valve A Circuit HighLow priorityEmissions System30–120 minutes for initial diagnosisP0459 relates to evap system purge control valve a circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P045AEGR B Control CircuitCheck soonEmissions System30–120 minutes for initial diagnosisP045A relates to egr b control circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P045BEGR B Control Circuit Range/PerformanceCheck soonEmissions System30–120 minutes for initial diagnosisP045B relates to egr b control circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P045CEGR B Control Circuit LowCheck soonEmissions System30–120 minutes for initial diagnosisP045C relates to egr b control circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P045DEGR B Control Circuit HighCheck soonEmissions System30–120 minutes for initial diagnosisP045D relates to egr b control circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P045EEGR B Control Stuck OpenCheck soonEmissions System30–120 minutes for initial diagnosisP045E relates to egr b control stuck open. Check the fault conditions and vehicle-specific procedure before replacing parts.P045FEGR B Control Stuck ClosedCheck soonEmissions System30–120 minutes for initial diagnosisP045F relates to egr b control stuck closed. Check the fault conditions and vehicle-specific procedure before replacing parts.P0465Purge Flow Sensor Circuit MalfunctionLow priorityEmissions System30–120 minutes for initial diagnosisP0465 indicates a fault related to purge flow sensor circuit malfunction. Learn the likely causes and a practical diagnostic order before replacing parts.P0466Purge Flow Sensor Circuit Range/PerformanceLow priorityEmissions System30–120 minutes for initial diagnosisP0466 indicates a fault related to purge flow sensor circuit range/performance. Learn the likely causes and a practical diagnostic order before replacing parts.P0467Purge Flow Sensor Circuit Low InputLow priorityEmissions System30–120 minutes for initial diagnosisP0467 indicates a fault related to purge flow sensor circuit low input. Learn the likely causes and a practical diagnostic order before replacing parts.P0468Purge Flow Sensor Circuit High InputLow priorityEmissions System30–120 minutes for initial diagnosisP0468 indicates a fault related to purge flow sensor circuit high input. Learn the likely causes and a practical diagnostic order before replacing parts.P0469Purge Flow Sensor Circuit IntermittentLow priorityEmissions System30–120 minutes for initial diagnosisP0469 indicates a fault related to purge flow sensor circuit intermittent. Learn the likely causes and a practical diagnostic order before replacing parts.P046ACatalyst Temperature Sensor 1/2 Correlation Bank 1Check soonEmissions System30–120 minutes for initial diagnosisP046A relates to catalyst temperature sensor 1/2 correlation bank 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P046BCatalyst Temperature Sensor 1/2 Correlation Bank 2Check soonEmissions System30–120 minutes for initial diagnosisP046B relates to catalyst temperature sensor 1/2 correlation bank 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P046CEGR Sensor A Circuit Range/PerformanceCheck soonEmissions System30–120 minutes for initial diagnosisP046C relates to egr sensor a circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P046DEGR Sensor A Circuit Intermittent/ErraticCheck soonEmissions System30–120 minutes for initial diagnosisP046D relates to egr sensor a circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P046EEGR Sensor B Circuit Range/PerformanceCheck soonEmissions System30–120 minutes for initial diagnosisP046E relates to egr sensor b circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P046FEGR Sensor B Circuit Intermittent/ErraticCheck soonEmissions System30–120 minutes for initial diagnosisP046F relates to egr sensor b circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P0470Exhaust Pressure Sensor Circuit MalfunctionCheck soonEmissions System30–120 minutes for initial diagnosisP0470 indicates a fault related to exhaust pressure sensor circuit malfunction. Learn the likely causes and a practical diagnostic order before replacing parts.P0471Exhaust Pressure Sensor Circuit Range/PerformanceCheck soonEmissions System30–120 minutes for initial diagnosisP0471 indicates a fault related to exhaust pressure sensor circuit range/performance. Learn the likely causes and a practical diagnostic order before replacing parts.P0472Exhaust Pressure Sensor Circuit Low InputCheck soonEmissions System30–120 minutes for initial diagnosisP0472 indicates a fault related to exhaust pressure sensor circuit low input. Learn the likely causes and a practical diagnostic order before replacing parts.P0473Exhaust Pressure Sensor Circuit High InputCheck soonEmissions System30–120 minutes for initial diagnosisP0473 indicates a fault related to exhaust pressure sensor circuit high input. Learn the likely causes and a practical diagnostic order before replacing parts.P0474Exhaust Pressure Sensor Circuit IntermittentCheck soonEmissions System30–120 minutes for initial diagnosisP0474 indicates a fault related to exhaust pressure sensor circuit intermittent. Learn the likely causes and a practical diagnostic order before replacing parts.P0486EGR Sensor B CircuitCheck soonEmissions System30–120 minutes for initial diagnosisP0486 relates to egr sensor b circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.