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.

Sensors & Electronics 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 1441–1464 of 2110

Most searched first

P254BPTO Speed Selector Sensor/Switch 1 Range/PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP254B relates to pto speed selector sensor/switch 1 range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P254CPTO Speed Selector Sensor/Switch 1 Circuit LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP254C relates to pto speed selector sensor/switch 1 circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P254DPTO Speed Selector Sensor/Switch 1 Circuit HighCheck soonSensors & Electronics30–120 minutes for initial diagnosisP254D relates to pto speed selector sensor/switch 1 circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P254EPTO Speed Selector Sensor/Switch 1 Circuit Intermittent/ErraticCheck soonSensors & Electronics30–120 minutes for initial diagnosisP254E relates to pto speed selector sensor/switch 1 circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P254FEngine Hood Switch CircuitCheck soonSensors & Electronics30–120 minutes for initial diagnosisP254F relates to engine hood switch circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P2550Torque Management Request Input Signal B LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2550 relates to torque management request input signal b low. Check the fault conditions and vehicle-specific procedure before replacing parts.P2551Torque Management Request Input Signal B HighCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2551 relates to torque management request input signal b high. Check the fault conditions and vehicle-specific procedure before replacing parts.P255APTO Speed Selector Sensor/Switch 2 Circuit/OpenCheck soonSensors & Electronics30–120 minutes for initial diagnosisP255A relates to pto speed selector sensor/switch 2 circuit/open. Check the fault conditions and vehicle-specific procedure before replacing parts.P255BPTO Speed Selector Sensor/Switch 2 Range/PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP255B relates to pto speed selector sensor/switch 2 range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P255CPTO Speed Selector Sensor/Switch 2 Circuit LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP255C relates to pto speed selector sensor/switch 2 circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P255DPTO Speed Selector Sensor/Switch 2 Circuit HighCheck soonSensors & Electronics30–120 minutes for initial diagnosisP255D relates to pto speed selector sensor/switch 2 circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P255EPTO Speed Selector Sensor/Switch 2 Circuit Intermittent/ErraticCheck soonSensors & Electronics30–120 minutes for initial diagnosisP255E relates to pto speed selector sensor/switch 2 circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P255FA/C Request A Circuit Range/PerformanceLow prioritySensors & Electronics30–120 minutes for initial diagnosisP255F relates to a/c request a circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P2561A/C Control Module Requested MIL IlluminationLow prioritySensors & Electronics30–120 minutes for initial diagnosisP2561 relates to a/c control module requested mil illumination. Check the fault conditions and vehicle-specific procedure before replacing parts.P2562Turbocharger Boost Control Position Sensor A CircuitCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2562 relates to turbocharger boost control position sensor a circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P2563Turbocharger Boost Control Position Sensor A Circuit Range/PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2563 relates to turbocharger boost control position sensor a circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P2564Turbocharger Boost Control Position Sensor A Circuit LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2564 relates to turbocharger boost control position sensor a circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P2565Turbocharger Boost Control Position Sensor A Circuit HighCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2565 relates to turbocharger boost control position sensor a circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P2566Turbocharger Boost Control Position Sensor A Circuit IntermittentCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2566 relates to turbocharger boost control position sensor a circuit intermittent. Check the fault conditions and vehicle-specific procedure before replacing parts.P256AEngine Idle Speed Selector Sensor/Switch Circuit/OpenCheck soonSensors & Electronics30–120 minutes for initial diagnosisP256A relates to engine idle speed selector sensor/switch circuit/open. Check the fault conditions and vehicle-specific procedure before replacing parts.P256BEngine Idle Speed Selector Sensor/Switch Range/PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP256B relates to engine idle speed selector sensor/switch range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P256CEngine Idle Speed Selector Sensor/Switch Circuit LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP256C relates to engine idle speed selector sensor/switch circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P256DEngine Idle Speed Selector Sensor/Switch Circuit HighCheck soonSensors & Electronics30–120 minutes for initial diagnosisP256D relates to engine idle speed selector sensor/switch circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P256EEngine Idle Speed Selector Sensor/Switch Circuit Intermittent/ErraticCheck soonSensors & Electronics30–120 minutes for initial diagnosisP256E relates to engine idle speed selector sensor/switch circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.