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.

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 4561–4584 of 9253

Most searched first

P2181Cooling System PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2181 relates to cooling system performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P2182Engine Coolant Temperature Sensor 2 CircuitCheck soonEngine Problems30–120 minutes for initial diagnosisP2182 relates to engine coolant temperature sensor 2 circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P2183Engine Coolant Temperature Sensor 2 Circuit Range/PerformanceCheck soonEngine Problems30–120 minutes for initial diagnosisP2183 relates to engine coolant temperature sensor 2 circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P2184Engine Coolant Temperature Sensor 2 Circuit LowCheck soonEngine Problems30–120 minutes for initial diagnosisP2184 relates to engine coolant temperature sensor 2 circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P2185Engine Coolant Temperature Sensor 2 Circuit HighCheck soonEngine Problems30–120 minutes for initial diagnosisP2185 relates to engine coolant temperature sensor 2 circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P2186Engine Coolant Temperature Sensor 2 Circuit Intermittent/ErraticCheck soonEngine Problems30–120 minutes for initial diagnosisP2186 relates to engine coolant temperature sensor 2 circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P2187System Too Lean at Idle Bank 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2187 relates to system too lean at idle bank 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2188System Too Rich at Idle Bank 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2188 relates to system too rich at idle bank 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2189System Too Lean at Idle Bank 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP2189 relates to system too lean at idle bank 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P218AThrottle Actuator B Control System - Idle Position Not LearnedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP218A relates to throttle actuator b control system - idle position not learned. Check the fault conditions and vehicle-specific procedure before replacing parts.P218BThrottle/Fuel Inhibit B CircuitCheck soonFuel System30–120 minutes for initial diagnosisP218B relates to throttle/fuel inhibit b circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P218CThrottle/Fuel Inhibit B Circuit Range/PerformanceCheck soonFuel System30–120 minutes for initial diagnosisP218C relates to throttle/fuel inhibit b circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P218DThrottle/Fuel Inhibit B Circuit LowCheck soonFuel System30–120 minutes for initial diagnosisP218D relates to throttle/fuel inhibit b circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P218EThrottle/Fuel Inhibit B Circuit HighCheck soonFuel System30–120 minutes for initial diagnosisP218E relates to throttle/fuel inhibit b circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P218FReductant No Flow DetectedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP218F relates to reductant no flow detected. Check the fault conditions and vehicle-specific procedure before replacing parts.P2190System Too Rich at Idle Bank 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP2190 relates to system too rich at idle bank 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P2191System Too Lean at Higher Load Bank 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2191 relates to system too lean at higher load bank 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2192System Too Rich at Higher Load Bank 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2192 relates to system too rich at higher load bank 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2193System Too Lean at Higher Load Bank 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP2193 relates to system too lean at higher load bank 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P2194System Too Rich at Higher Load Bank 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP2194 relates to system too rich at higher load bank 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P2196O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2196 relates to o2 sensor signal biased/stuck rich bank 1 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2197O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2197 relates to o2 sensor signal biased/stuck lean bank 2 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2198O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2198 relates to o2 sensor signal biased/stuck rich bank 2 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2199Intake Air Temperature Sensor 1/2 CorrelationCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2199 relates to intake air temperature sensor 1/2 correlation. Check the fault conditions and vehicle-specific procedure before replacing parts.