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Diagnostic Codes List

This page provides a structured reference list of automotive Diagnostic Trouble Codes (DTCs) used by modern vehicle onboard diagnostic systems.

Diagnostic codes are generated by the ECU when a fault is detected in the engine, transmission, emissions system, vehicle network, or other electronic control systems. Each code represents a specific fault condition and serves as the starting point for vehicle diagnostics and troubleshooting.

This Diagnostic Codes List allows technicians and automotive professionals to browse fault codes by system category, quickly identify code meanings, and access detailed diagnostic information for each individual code.

By selecting a specific diagnostic code, you can view in-depth explanations including fault descriptions, affected systems, common causes, diagnostic procedures, and recommended inspection steps based on real-world diagnostic scenarios.

This list is designed to support efficient fault identification and accurate diagnosis using professional diagnostic tools, live data analysis, and vehicle-specific diagnostic workflows.

Select by System

P0651

Diagnostic trouble code P0651 indicates a malfunction in the exhaust gas recirculation (EGR) sensor circuit

P0652

Diagnostic trouble code P0652 indicates a malfunction in the EGR valve position sensor circuit

P0653

Diagnostic trouble code P0653 indicates a malfunction in the throttle position sensor circuit

P0654

Diagnostic trouble code P0654 indicates a malfunction in the throttle actuator control circuit

P0655

Diagnostic trouble code P0655 indicates a malfunction in the intake air temperature sensor circuit

P0656

Diagnostic trouble code P0656 indicates an issue with the engine control module (ECM) wiring

P0657

Diagnostic trouble code P0657 indicates a malfunction in the fuel injector control circuit

P0658

Diagnostic trouble code P0658 indicates a malfunction in the exhaust gas recirculation (EGR) valve control circuit

P0659

Diagnostic trouble code P0659 indicates a malfunction in the camshaft position sensor circuit

P0660

Diagnostic trouble code P0660 indicates a malfunction in the intake manifold runner control circuit

P0661

Diagnostic trouble code P0661 indicates a malfunction in the intake manifold runner control solenoid circuit

P0662

Diagnostic trouble code P0662 indicates an issue with the intake manifold runner control solenoid performance

P0663

Diagnostic trouble code P0663 indicates a malfunction in the intake manifold runner control solenoid circuit range

P0664

Diagnostic trouble code P0664 indicates a malfunction in the intake air temperature sensor circuit

P0665

Diagnostic trouble code P0665 indicates a malfunction in the intake manifold runner control solenoid circuit

P0666

Diagnostic trouble code P0666 indicates a malfunction in the exhaust gas recirculation (EGR) valve sensor circuit

P0667

Diagnostic trouble code P0667 indicates a malfunction in the intake manifold runner control sensor circuit

P0668

Diagnostic trouble code P0668 indicates a malfunction in the intake manifold runner control system

P0669

Diagnostic trouble code P0669 indicates a malfunction in the intake manifold runner control solenoid position sensor circuit

P0670

Diagnostic trouble code P0670 indicates a malfunction in the glow plug control circuit

P0671

Diagnostic trouble code P0671 indicates a malfunction in the glow plug control circuit for cylinder 1

P0672

Diagnostic trouble code P0672 indicates a malfunction in the glow plug control circuit for cylinder 2

P0673

Diagnostic trouble code P0673 indicates a malfunction in the glow plug control circuit for cylinder 3

P0674

Diagnostic trouble code P0674 indicates a malfunction in the glow plug control circuit for cylinder 4

P0675

Diagnostic trouble code P0675 indicates a malfunction in the glow plug control circuit for cylinder 5

P0676

Diagnostic trouble code P0676 indicates a malfunction in the glow plug control circuit for cylinder 6

P0677

Diagnostic trouble code P0677 indicates a malfunction in the glow plug control circuit for cylinder 7

P0678

Diagnostic trouble code P0678 indicates a malfunction in the glow plug control circuit for cylinder 8

P0679

Diagnostic trouble code P0679 indicates a malfunction in the fuel pressure sensor circuit

P0680

Diagnostic trouble code P0680 indicates a malfunction in the engine control module (ECM) power relay circuit

P0681

Diagnostic trouble code P0681 indicates a malfunction in the engine control module (ECM) power relay control circuit

P0682

Diagnostic trouble code P0682 indicates a malfunction in the engine control module (ECM) power circuit

P0683

Diagnostic trouble code P0683 indicates a malfunction in the throttle actuator control system

P0684

Diagnostic trouble code P0684 indicates a malfunction in the engine control module (ECM) control circuit

P0685

Diagnostic trouble code P0685 indicates a malfunction in the engine control module (ECM) cooling fan control circuit

P0690

Diagnostic trouble code P0690 indicates a malfunction in the intake air temperature sensor circuit

P0691

Diagnostic trouble code P0691 indicates a malfunction in the intake air temperature sensor performance

P0692

Diagnostic trouble code P0692 indicates a malfunction in the intake air temperature sensor circuit

P0693

Diagnostic trouble code P0693 indicates a malfunction in the oxygen sensor heater control circuit

P0694

Diagnostic trouble code P0694 indicates a malfunction in the mass air flow (MAF) sensor circuit

P0695

Diagnostic trouble code P0695 indicates a malfunction in the fuel pressure sensor circuit

P0696

Diagnostic trouble code P0696 indicates a malfunction in the intake manifold temperature sensor circuit

P0697

Diagnostic trouble code P0697 indicates a malfunction in the engine coolant temperature sensor circuit

P0698

Diagnostic trouble code P0698 indicates a malfunction in the throttle actuator control circuit

P0699

Diagnostic trouble code P0699 indicates a malfunction in the mass air flow sensor circuit

P0701

Diagnostic trouble code P0701 indicates a malfunction in the transmission shift control circuit

P0702

Diagnostic trouble code P0702 indicates a malfunction in the transmission range sensor circuit

P0703

Diagnostic trouble code P0703 indicates a malfunction in the transmission fluid temperature sensor circuit

P0704

Diagnostic trouble code P0704 indicates a malfunction in the clutch switch circuit

P0705

Diagnostic trouble code P0705 indicates a malfunction in the transmission neutral safety switch circuit

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