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 97–120 of 515

Most searched first

P0487EGR Throttle Control Circuit A /OpenCheck soonEmissions System30–120 minutes for initial diagnosisP0487 relates to egr throttle control circuit a /open. Check the fault conditions and vehicle-specific procedure before replacing parts.P0488EGR Throttle Control Circuit A Range/PerformanceCheck soonEmissions System30–120 minutes for initial diagnosisP0488 relates to egr throttle control circuit a range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P0489EGR A Control Circuit LowCheck soonEmissions System30–120 minutes for initial diagnosisP0489 relates to egr a control circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P0490EGR A Control Circuit HighCheck soonEmissions System30–120 minutes for initial diagnosisP0490 relates to egr a control circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P0496Evaporative Emission System High Purge FlowLow priorityEmissions System30–120 minutes for initial diagnosisP0496 indicates a fault related to evaporative emission system high purge flow. Learn the likely causes and a practical diagnostic order before replacing parts.P0497Evaporative Emission System Low Purge FlowLow priorityEmissions System30–120 minutes for initial diagnosisP0497 indicates a fault related to evaporative emission system low purge flow. Learn the likely causes and a practical diagnostic order before replacing parts.P0498Evaporative Emission System Vent Valve Control Circuit LowLow priorityEmissions System30–120 minutes for initial diagnosisP0498 indicates a fault related to evaporative emission system vent valve control circuit low. Learn the likely causes and a practical diagnostic order before replacing parts.P0499Evaporative Emission System Vent Valve Control Circuit HighLow priorityEmissions System30–120 minutes for initial diagnosisP0499 indicates a fault related to evaporative emission system vent valve control circuit high. Learn the likely causes and a practical diagnostic order before replacing parts.P049AEGR B FlowCheck soonEmissions System30–120 minutes for initial diagnosisP049A relates to egr b flow. Check the fault conditions and vehicle-specific procedure before replacing parts.P049BEGR B Flow Insufficient DetectedCheck soonEmissions System30–120 minutes for initial diagnosisP049B relates to egr b flow insufficient detected. Check the fault conditions and vehicle-specific procedure before replacing parts.P049CEGR B Flow Excessive DetectedCheck soonEmissions System30–120 minutes for initial diagnosisP049C relates to egr b flow excessive detected. Check the fault conditions and vehicle-specific procedure before replacing parts.P049DEGR A Control Position Exceeded Learning LimitCheck soonEmissions System30–120 minutes for initial diagnosisP049D relates to egr a control position exceeded learning limit. Check the fault conditions and vehicle-specific procedure before replacing parts.P049EEGR B Control Position Exceeded Learning LimitCheck soonEmissions System30–120 minutes for initial diagnosisP049E relates to egr b control position exceeded learning limit. Check the fault conditions and vehicle-specific procedure before replacing parts.P04ABEVAP System Purge Control Valve B Circuit/OpenLow priorityEmissions System30–120 minutes for initial diagnosisP04AB relates to evap system purge control valve b circuit/open. Check the fault conditions and vehicle-specific procedure before replacing parts.P04ACEVAP System Purge Control Valve B Circuit LowLow priorityEmissions System30–120 minutes for initial diagnosisP04AC relates to evap system purge control valve b circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P04ADEVAP System Purge Control Valve B Circuit HighLow priorityEmissions System30–120 minutes for initial diagnosisP04AD relates to evap system purge control valve b circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P04AEEVAP System Purge Control Valve B Performance/Stuck OpenLow priorityEmissions System30–120 minutes for initial diagnosisP04AE relates to evap system purge control valve b performance/stuck open. Check the fault conditions and vehicle-specific procedure before replacing parts.P04AFEVAP System Purge Control Valve B Stuck ClosedLow priorityEmissions System30–120 minutes for initial diagnosisP04AF relates to evap system purge control valve b stuck closed. Check the fault conditions and vehicle-specific procedure before replacing parts.P04CEEGR Temperature Sensor C CircuitCheck soonEmissions System30–120 minutes for initial diagnosisP04CE relates to egr temperature sensor c circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P04CFEGR Temperature Sensor C Circuit Range/PerformanceCheck soonEmissions System30–120 minutes for initial diagnosisP04CF relates to egr temperature sensor c circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P04D0EGR Temperature Sensor C Circuit LowCheck soonEmissions System30–120 minutes for initial diagnosisP04D0 relates to egr temperature sensor c circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P04D1EGR Temperature Sensor C Circuit HighCheck soonEmissions System30–120 minutes for initial diagnosisP04D1 relates to egr temperature sensor c circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P04D2EGR Temperature Sensor C Circuit Intermittent/ErraticCheck soonEmissions System30–120 minutes for initial diagnosisP04D2 relates to egr temperature sensor c circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P04D8Excessive Time To Enter Closed Loop EGR ControlCheck soonEmissions System30–120 minutes for initial diagnosisP04D8 relates to excessive time to enter closed loop egr control. Check the fault conditions and vehicle-specific procedure before replacing parts.