Generic Codes

Generic OBD2 codes are standardized codes that apply to all cars that are OBD2 compliant, regardless of the make or model. 

Our collection of articles on this page provides a wealth of information about these codes, going beyond just an explanation of what they mean. We analyze each code in detail, providing technical explanations, common causes, symptoms to look out for, and recommended solutions for each issue.

So why wait? Start exploring now!

In a hurry? Quickly jump to the code you're facing:

U03FD: ISO/SAE Reserved

By OBD Codex / February 11, 2024

The U03FD code is a generic ISO/SAE Reserved code that may appear in your vehicle's diagnostic system. Read on to learn more about it and what you should do to deal with it.

U03FE: ISO/SAE Reserved

By OBD Codex / February 12, 2024

The U03FE code is a generic ISO/SAE Reserved code that may appear in your vehicle's diagnostic system. Read on to learn more about it and what you should do to deal with it.

U03FF: ISO/SAE Reserved

By OBD Codex / February 05, 2024

The U03FF code is a generic ISO/SAE Reserved code that may appear in your vehicle's diagnostic system. Read on to learn more about it and what you should do to deal with it.

U0400: ISO/SAE Reserved

By OBD Codex / January 16, 2024

The U0400 code is a generic ISO/SAE Reserved code that may appear in your vehicle's diagnostic system. Read on to learn more about it and what you should do to deal with it.

U0401: Invalid Data Received From ECM/PCM "A"

By OBD Codex / February 01, 2024

Is the U0401 code causing communication issues in your vehicle? Read on to learn how to deal with this communication network problem and get your vehicle back on the road.

U0402: Invalid Data Received From Transmission Control Module (TCM)

By OBD Codex / February 05, 2024

Is the U0402 code causing communication issues in your vehicle? Read on to learn how to deal with this communication network problem and get your vehicle back on the road.

U0403: Invalid Data Received From Transfer Case Control Module

By OBD Codex / January 27, 2024

Is the U0403 code causing communication issues in your vehicle? Read on to learn how to deal with this communication network problem and get your vehicle back on the road.

U0404: Invalid Data Received From Gear Shift Control Module "A"

By OBD Codex / January 15, 2024

Is the U0404 code causing communication issues in your vehicle? Read on to learn how to deal with this communication network problem and get your vehicle back on the road.

U0405: Invalid Data Received From Cruise Control Module

By OBD Codex / January 27, 2024

Is the U0405 code causing communication issues in your vehicle? Read on to learn how to deal with this communication network problem and get your vehicle back on the road.

U0406: Invalid Data Received From Fuel Injector Control Module

By OBD Codex / January 20, 2024

Is the U0406 code causing communication issues in your vehicle? Read on to learn how to deal with this communication network problem and get your vehicle back on the road.