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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 913–936 of 1939

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P2174Throttle Actuator Control System - Sudden Low Air Flow DetectedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2174 relates to throttle actuator control system - sudden low air flow detected. Check the fault conditions and vehicle-specific procedure before replacing parts.P2175Throttle Actuator Control System - Low Air Flow DetectedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2175 relates to throttle actuator control system - low air flow detected. Check the fault conditions and vehicle-specific procedure before replacing parts.P2176Throttle Actuator A Control System - Idle Position Not LearnedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP2176 relates to throttle actuator a control system - idle position not learned. Check the fault conditions and vehicle-specific procedure before replacing parts.P2177System Too Lean Off Idle Bank 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2177 relates to system too lean off idle bank 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2178System Too Rich Off Idle Bank 1Check soonSensors & Electronics30–120 minutes for initial diagnosisP2178 relates to system too rich off idle bank 1. Check the fault conditions and vehicle-specific procedure before replacing parts.P2179System Too Lean Off Idle Bank 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP2179 relates to system too lean off idle bank 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P2180System Too Rich Off Idle Bank 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP2180 relates to system too rich off idle bank 2. Check the fault conditions and vehicle-specific procedure before replacing parts.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.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.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.P21A8Reductant Level Sensor B CircuitCheck soonSensors & Electronics30–120 minutes for initial diagnosisP21A8 relates to reductant level sensor b circuit. Check the fault conditions and vehicle-specific procedure before replacing parts.P21A9Reductant Level Sensor B Circuit Range/PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP21A9 relates to reductant level sensor b circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.