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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 1177–1200 of 1939

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P239ADiesel Intake Air Flow B Position Sensor Circuit Intermittent/ErraticCheck soonSensors & Electronics30–120 minutes for initial diagnosisP239A relates to diesel intake air flow b position sensor circuit intermittent/erratic. Check the fault conditions and vehicle-specific procedure before replacing parts.P239BDiesel Intake Air Flow B Control Motor Current Range/PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP239B relates to diesel intake air flow b control motor current range/performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P239CDiesel Intake Air Flow B Control System - High Air Flow DetectedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP239C relates to diesel intake air flow b control system - high air flow detected. Check the fault conditions and vehicle-specific procedure before replacing parts.P239DDiesel Intake Air Flow B Control System - Low Air Flow DetectedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP239D relates to diesel intake air flow b control system - low air flow detected. Check the fault conditions and vehicle-specific procedure before replacing parts.P239EO2 Sensor Out of Range During Deceleration Bank 1 Sensor 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP239E relates to o2 sensor out of range during deceleration bank 1 sensor 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P239FO2 Sensor Out of Range During Deceleration Bank 2 Sensor 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP239F relates to o2 sensor out of range during deceleration bank 2 sensor 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A0O2 Sensor Exhaust Sample Error Bank 1 Sensor 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP23A0 relates to o2 sensor exhaust sample error bank 1 sensor 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A1O2 Sensor Exhaust Sample Error Bank 2 Sensor 2Check soonSensors & Electronics30–120 minutes for initial diagnosisP23A1 relates to o2 sensor exhaust sample error bank 2 sensor 2. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A2Exhaust Heat Exchanger Exhaust Bypass Valve B Control Circuit/OpenCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A2 relates to exhaust heat exchanger exhaust bypass valve b control circuit/open. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A3Exhaust Heat Exchanger Exhaust Bypass Valve B Control Circuit LowCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A3 relates to exhaust heat exchanger exhaust bypass valve b control circuit low. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A4Exhaust Heat Exchanger Exhaust Bypass Valve B Control Circuit HighCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A4 relates to exhaust heat exchanger exhaust bypass valve b control circuit high. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A5Exhaust Heat Exchanger Exhaust Bypass Valve B Control PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A5 relates to exhaust heat exchanger exhaust bypass valve b control performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A6Exhaust Heat Exchanger Exhaust Bypass Valve B Stuck OpenCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A6 relates to exhaust heat exchanger exhaust bypass valve b stuck open. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A7Exhaust Heat Exchanger Exhaust Bypass Valve B Stuck ClosedCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A7 relates to exhaust heat exchanger exhaust bypass valve b stuck closed. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A8Exhaust Heat Exchanger Exhaust Bypass Valve B Position Sensor Stop PerformanceCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A8 relates to exhaust heat exchanger exhaust bypass valve b position sensor stop performance. Check the fault conditions and vehicle-specific procedure before replacing parts.P23A9Communication Fault – Forced Engine ShutdownCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23A9 relates to communication fault – forced engine shutdown. Check the fault conditions and vehicle-specific procedure before replacing parts.P23AATurbocharger/Supercharger Bypass Valve A StuckCheck soonSensors & Electronics30–120 minutes for initial diagnosisP23AA relates to turbocharger/supercharger bypass valve a stuck. Check the fault conditions and vehicle-specific procedure before replacing parts.P23ABNOx Sensor Processor Performance Bank 1 Sensor 3Check soonSensors & Electronics30–120 minutes for initial diagnosisP23AB relates to nox sensor processor performance bank 1 sensor 3. Check the fault conditions and vehicle-specific procedure before replacing parts.P23ACNOx Sensor Circuit Bank 1 Sensor 3Check soonSensors & Electronics30–120 minutes for initial diagnosisP23AC relates to nox sensor circuit bank 1 sensor 3. Check the fault conditions and vehicle-specific procedure before replacing parts.P23ADNOx Sensor Circuit Range/Performance Bank 1 Sensor 3Check soonSensors & Electronics30–120 minutes for initial diagnosisP23AD relates to nox sensor circuit range/performance bank 1 sensor 3. Check the fault conditions and vehicle-specific procedure before replacing parts.P23AENOx Sensor Circuit Low Bank 1 Sensor 3Check soonSensors & Electronics30–120 minutes for initial diagnosisP23AE relates to nox sensor circuit low bank 1 sensor 3. Check the fault conditions and vehicle-specific procedure before replacing parts.P23AFNOx Sensor Circuit High Bank 1 Sensor 3Check soonSensors & Electronics30–120 minutes for initial diagnosisP23AF relates to nox sensor circuit high bank 1 sensor 3. Check the fault conditions and vehicle-specific procedure before replacing parts.P23B0NOx Sensor Circuit Intermittent Bank 1 Sensor 3Check soonSensors & Electronics30–120 minutes for initial diagnosisP23B0 relates to nox sensor circuit intermittent bank 1 sensor 3. Check the fault conditions and vehicle-specific procedure before replacing parts.P23B1NOx Sensor Heater Control Circuit/Open Bank 1 Sensor 3Check soonSensors & Electronics30–120 minutes for initial diagnosisP23B1 relates to nox sensor heater control circuit/open bank 1 sensor 3. Check the fault conditions and vehicle-specific procedure before replacing parts.