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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 505–528 of 7353

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P026ACharge Air Cooler Efficiency Below ThresholdCheck soonSensors & Electronics30–120 minutes for initial diagnosisP026A relates to charge air cooler efficiency below threshold. Check the fault conditions and vehicle-specific procedure before replacing parts.P026BInjection Timing PerformanceCheck soonFuel System30–120 minutes for initial diagnosisP026B relates to injection timing performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P026CFuel Injection Quantity A Lower Than ExpectedCheck soonFuel System30–120 minutes for initial diagnosisP026C relates to fuel injection quantity a lower than expected. Check the fault conditions and vehicle-specific procedure before replacing parts.P026DFuel Injection Quantity A Higher Than ExpectedCheck soonFuel System30–120 minutes for initial diagnosisP026D relates to fuel injection quantity a higher than expected. Check the fault conditions and vehicle-specific procedure before replacing parts.P026ECharge Air Cooler Coolant Pump A PerformanceCheck soonEngine Problems30–120 minutes for initial diagnosisP026E relates to charge air cooler coolant pump a performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P026FCoolant Thermostat PerformanceCheck soonEngine Problems30–120 minutes for initial diagnosisP026F relates to coolant thermostat performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P0270Cylinder 4 Injector A Circuit LowCheck soonFuel System30–120 minutes for initial diagnosisP0270 relates to cylinder 4 injector a circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P0271Cylinder 4 Injector A Circuit HighCheck soonFuel System30–120 minutes for initial diagnosisP0271 relates to cylinder 4 injector a circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P0272Cylinder 4 Contribution/BalanceCheck soonEngine Problems30–120 minutes for initial diagnosisP0272 relates to cylinder 4 contribution/balance. Check the fault conditions and vehicle-specific procedure before replacing parts.P0273Cylinder 5 Injector A Circuit LowCheck soonFuel System30–120 minutes for initial diagnosisP0273 relates to cylinder 5 injector a circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P0274Cylinder 5 Injector A Circuit HighCheck soonFuel System30–120 minutes for initial diagnosisP0274 relates to cylinder 5 injector a circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P0275Cylinder 5 Contribution/BalanceCheck soonEngine Problems30–120 minutes for initial diagnosisP0275 relates to cylinder 5 contribution/balance. Check the fault conditions and vehicle-specific procedure before replacing parts.P0276Cylinder 6 Injector A Circuit LowCheck soonFuel System30–120 minutes for initial diagnosisP0276 relates to cylinder 6 injector a circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P0277Cylinder 6 Injector A Circuit HighCheck soonFuel System30–120 minutes for initial diagnosisP0277 relates to cylinder 6 injector a circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P0278Cylinder 6 Contribution/BalanceCheck soonEngine Problems30–120 minutes for initial diagnosisP0278 relates to cylinder 6 contribution/balance. Check the fault conditions and vehicle-specific procedure before replacing parts.P0279Cylinder 7 Injector A Circuit LowCheck soonFuel System30–120 minutes for initial diagnosisP0279 relates to cylinder 7 injector a circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P027AFuel Pump Module B Control Circuit/OpenCheck soonFuel System30–120 minutes for initial diagnosisP027A relates to fuel pump module b control circuit/open. Check the fault conditions and vehicle-specific procedure before replacing parts.P027BFuel Pump Module B Control Circuit Range/PerformanceCheck soonFuel System30–120 minutes for initial diagnosisP027B relates to fuel pump module b control circuit range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P027CFuel Pump Module B Control Circuit LowCheck soonFuel System30–120 minutes for initial diagnosisP027C relates to fuel pump module b control circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P027DFuel Pump Module B Control Circuit HighCheck soonFuel System30–120 minutes for initial diagnosisP027D relates to fuel pump module b control circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P027ECold Start Fuel Injection Quantity A Lower Than ExpectedCheck soonFuel System30–120 minutes for initial diagnosisP027E relates to cold start fuel injection quantity a lower than expected. Check the fault conditions and vehicle-specific procedure before replacing parts.P027FCold Start Fuel Injection Quantity A Higher Than ExpectedCheck soonFuel System30–120 minutes for initial diagnosisP027F relates to cold start fuel injection quantity a higher than expected. Check the fault conditions and vehicle-specific procedure before replacing parts.P0280Cylinder 7 Injector A Circuit HighCheck soonFuel System30–120 minutes for initial diagnosisP0280 relates to cylinder 7 injector a circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P0281Cylinder 7 Contribution/BalanceCheck soonEngine Problems30–120 minutes for initial diagnosisP0281 relates to cylinder 7 contribution/balance. Check the fault conditions and vehicle-specific procedure before replacing parts.