AutoFixDB

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The most complete database of 50,000+ OBD-II codes and symptom guides to help you fix your car.

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Troubleshoot by Symptom

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Fuel, Air & Emission 2935 issues Noises & Vibration 2236 issues Chassis & Handling 987 issues Ignition & Starting 56 issues Fluids, Leaks & Smells 681 issues Body, Electrical & Interior 505 issues Engine Mechanical & Cooling 567 issues Other 283 issues

Browse by Code Type

Powertrain Codes (P)

Powertrain codes relate to the engine, transmission, and associated drivetrain accessories.

Chassis Codes (C)

Chassis codes cover anti-lock braking (ABS), electronic suspension and steering systems.

Body Codes (B)

Body codes relate to body features including air conditioning, airbag, and instrument panel.

Network Codes (U)

Network codes cover communications between vehicle modules and control units.

In-Depth Guides

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Live Data Analysis

Learn how to interpret OBD-II PIDs and make sense of your sensor data.
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Scanner & App Guide

Top OBD apps comparison: Torque vs GeekOBD vs others for your needs.
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Sensor Reference

Quick lookup chart for normal operating ranges (MAF, Fuel Trim, ECT, etc).

Common Questions

What is an OBD-II code?

An OBD-II (On-Board Diagnostics II) code is a standardized diagnostic trouble code that your vehicle's computer generates when it detects a problem. These codes help identify issues with the engine, transmission, emissions, and other systems.

What does the check engine light mean?

The check engine light (CEL) or malfunction indicator lamp (MIL) indicates that your vehicle's computer has detected a problem and stored a diagnostic trouble code. It can range from minor issues like a loose gas cap to serious problems requiring immediate attention.

How do I read OBD-II codes?

You need an OBD-II scanner to read codes. Plug the scanner into the OBD-II port (usually under the dashboard), turn on the ignition, and follow the scanner's instructions to retrieve stored codes. Many auto parts stores offer free code reading.

What do P, C, B, and U codes mean?

OBD-II codes are categorized by their first letter: P (Powertrain) covers engine and transmission, C (Chassis) covers ABS and steering, B (Body) covers airbags and A/C, and U (Network) covers communication between modules.