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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 1201–1224 of 1570

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P2139Throttle/Pedal Position Sensor/Switch D/F Voltage CorrelationCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP2139 relates to throttle/pedal position sensor/switch d/f voltage correlation. Check the fault conditions and vehicle-specific procedure before replacing parts.P2140Throttle/Pedal Position Sensor/Switch E/F Voltage CorrelationCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP2140 relates to throttle/pedal position sensor/switch e/f voltage correlation. Check the fault conditions and vehicle-specific procedure before replacing parts.P21C2Reductant Heater Relay Control Circuit/OpenCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21C2 relates to reductant heater relay control circuit/open. Check the fault conditions and vehicle-specific procedure before replacing parts.P21C3Reductant Heater Relay Control Circuit LowCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21C3 relates to reductant heater relay control circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P21C4Reductant Heater Relay Control Circuit HighCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21C4 relates to reductant heater relay control circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P21C7Reductant Control Module Power Relay/Relays Control Circuit/OpenCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21C7 relates to reductant control module power relay/relays control circuit/open. Check the fault conditions and vehicle-specific procedure before replacing parts.P21C8Reductant Control Module Power Relay/Relays Control Circuit LowCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21C8 relates to reductant control module power relay/relays control circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P21C9Reductant Control Module Power Relay/Relays Control Circuit HighCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21C9 relates to reductant control module power relay/relays control circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P21CAReductant Control Module Supply Voltage CircuitCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21CA relates to reductant control module supply voltage circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P21CBReductant Control Module Supply Voltage LowCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21CB relates to reductant control module supply voltage low. Check the fault conditions and vehicle-specific procedure before replacing parts.P21CCReductant Control Module Supply Voltage HighCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21CC relates to reductant control module supply voltage high. Check the fault conditions and vehicle-specific procedure before replacing parts.P21CDReductant Quality Module Supply Voltage LowCheck soonElectrical & Charging System30–120 minutes for initial diagnosisP21CD relates to reductant quality module supply voltage low. Check the fault conditions and vehicle-specific procedure before replacing parts.P220ANOx Sensor Supply Voltage Circuit Bank 1 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP220A relates to nox sensor supply voltage circuit bank 1 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P220BNOx Sensor Supply Voltage Circuit Bank 1 Sensor 2Check soonElectrical & Charging System30–120 minutes for initial diagnosisP220B relates to nox sensor supply voltage circuit bank 1 sensor 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P220CNOx Sensor Supply Voltage Circuit Bank 2 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP220C relates to nox sensor supply voltage circuit bank 2 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P220DNOx Sensor Supply Voltage Circuit Bank 2 Sensor 2Check soonElectrical & Charging System30–120 minutes for initial diagnosisP220D relates to nox sensor supply voltage circuit bank 2 sensor 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P2243O2 Sensor Reference Voltage Circuit/Open Bank 1 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2243 relates to o2 sensor reference voltage circuit/open bank 1 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2244O2 Sensor Reference Voltage Performance Bank 1 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2244 relates to o2 sensor reference voltage performance bank 1 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2245O2 Sensor Reference Voltage Circuit Low Bank 1 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2245 relates to o2 sensor reference voltage circuit low bank 1 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2246O2 Sensor Reference Voltage Circuit High Bank 1 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2246 relates to o2 sensor reference voltage circuit high bank 1 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2247O2 Sensor Reference Voltage Circuit/Open Bank 2 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2247 relates to o2 sensor reference voltage circuit/open bank 2 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2248O2 Sensor Reference Voltage Performance Bank 2 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2248 relates to o2 sensor reference voltage performance bank 2 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2249O2 Sensor Reference Voltage Circuit Low Bank 2 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2249 relates to o2 sensor reference voltage circuit low bank 2 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2250O2 Sensor Reference Voltage Circuit High Bank 2 Sensor 1Check soonElectrical & Charging System30–120 minutes for initial diagnosisP2250 relates to o2 sensor reference voltage circuit high bank 2 sensor 1. Check the fault conditions and vehicle-specific procedure before replacing parts.