OBD-II Error Code Lookup

OBD-II error code lookup results identify the system and fault description behind a five-character diagnostic trouble code. A code gives you a place to start testing, but it does not prove that the named part has failed.

What This Lookup Provides

• Accepts P, B, C, and U codes with numbers or the letters A through F.
• Explains common codes in plain English.
• Suggests checks that preserve diagnostic evidence and avoid guesswork.
• Identifies the code family even when the exact code is not in this quick reference.

Use the exact year, make, model, engine, and module when you check vehicle service information. The same-looking fault can require different tests on different vehicles.

Read the Five Characters Correctly

The first letter names the broad system: P is powertrain, B is body, C is chassis, and U is network communication. The next four characters can contain digits and the letters A through F, so a code such as P0A80 is valid. SAE J2012 defines standardized DTC formats and also reserves ranges for vehicle-maker use. See the current SAE diagnostic trouble code standard.

A Code Is a Test Starting Point

A circuit code can be caused by a component, connector, wire, power supply, ground, or control module. A lean, rich, misfire, or efficiency code describes a result the controller detected, not the one part to replace. Record all stored and pending codes, freeze-frame data, warning-light behavior, and symptoms before disconnecting the battery or clearing anything.

Use Scanner Data Before Clearing Codes

Look for related codes and compare live data with service specifications. After a confirmed repair, follow the vehicle maker's verification procedure. Clearing codes too early can erase useful context and reset emissions readiness monitors. The California Air Resources Board explains how OBD II stores information so a technician can find and repair detected problems.

Act Promptly if the Light Flashes

A steady check engine light usually calls for diagnosis soon. A flashing light can indicate a severe misfire that may damage the catalytic converter. Reduce speed and engine load, then seek service as soon as it is safe. Follow the owner's manual if the engine shakes, loses power, overheats, or shows another warning. The EPA's OBD warning-light guidance explains the difference. For cost context, see the site's check engine light repair statistics.