OBD-II Codes List Lookup - Pitstop

OBD-II Codes List Lookup Tool

When your truck’s check engine light turns on, it can be daunting knowing you’ll spend considerable time sifting through J1939 or OBD-II codes list to determine if the issue is severe. Discovering a fault code management solution is crucial for diagnosing your vehicle’s issues. It assists in understanding J1939 or OBD-II code lists, informing you when to address issues. Use Pitstop’s free fault code lookup tool to quickly obtain a definition of the alert, so you can determine if your maintenance shop should close out the fault code or address it immediately.

J1939 & OBD-II Fault Code Priority Descriptions:


Book an appointment right away with your mechanic.


Book an appointment in the coming weeks.


Often a “noisy” fault code that is likely fine until your next service visit.

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A Guide to Understanding Fault Codes

What is a fault code?

Fault codes, or Diagnostic Trouble Codes (DTCs), are essential tools for identifying and diagnosing vehicle problems requiring action. By consulting an OBD-II codes list or a J1939 fault code list, technicians and vehicle owners can pinpoint malfunction sources and decide on necessary repairs.

What are the different types of fault codes?

There are two primary fault codes: OBD-II and J1939. OBD-II (On-Board Diagnostics II) is a standardized system in most vehicles since 1996. These codes consist of a letter and four digits, with the letter indicating the problem’s general area (P for Powertrain, B for Body, C for Chassis, and U for Network communication and vehicle control systems).

In contrast, J1939 fault codes are mainly used in heavy-duty commercial vehicles. They consist of numerical Suspect Parameter Numbers (SPNs) corresponding to specific components or systems. These codes often pair with a Failure Mode Identifier (FMI) number for further clarification on the malfunction’s nature.

Where do fault codes come from?

Vehicle Electronic Control Modules (ECMs) generate fault codes. ECMs continuously monitor sensors and components, producing a fault code stored in the vehicle’s memory when detecting a parameter outside the acceptable range. Accessing these stored fault codes with specialized diagnostic tools allows efficient identification and resolution of vehicle issues. Familiarize yourself with an OBD-II codes list and a J1939 fault code list to better understand and tackle vehicle malfunctions.

What are the most common fault codes? 

Numerous fault codes exist for both OBD-II and J1939 systems, and the most common specific codes vary depending on the vehicle’s make and model. However, here are some examples of common fault codes that may be encountered.

It’s important to note that fault codes can be generated for various reasons, and these codes are just a starting point for diagnosing vehicle issues. Fleet maintenance software can remotely diagnose these fault codes. However, a qualified mechanic must conduct additional testing and inspections to determine the problem’s root cause and recommend appropriate repairs.

OBD-II Codes List Lookup Tool