Diagnostic Code Information
Decode Your Vehicle's Secrets: Your Guide to Understanding Diagnostic CodesÂ
OBD-II codes are part of the self-diagnostic system that all cars come with. The OBD system uses Diagnostic Trouble Codes (DTC) to tell you which specific component has an issue. The five-digit codes and are made up of four different subsets of codes that indicate where in the vehicle the malfunction lies.
The first number in the DTC tells you if the code is specific to the vehicle manufacturer or a generic code that applies to all OBD-II systems. The last three numbers tell you specific information on the vehicle system or circuit that is running into trouble.
Powertrain Codes (P-Codes)
"P codes" refer to powertrain-related diagnostic trouble codes. These codes relate to issues with the engine, transmission, and emissions control systems.
Powertrain-related diagnostic trouble codes typically start with the letter "P" followed by four digits. For example, P0300 is a common code for a random misfire detected by the engine control module, while P0440 may indicate an issue with the vehicle's evaporative emissions control system.
Body Codes (B-Codes)
"B codes" refer to body-related diagnostic trouble codes. These codes relate to issues with a variety of body-related systems and components, including the airbags, seatbelts, power windows, and other non-engine systems.
Body-related diagnostic trouble codes typically start with the letter "B" followed by four digits. For example, B0001 is a common code for an airbag-related issue, while B1234 may relate to an issue with the power windows or locks.
Chassis Codes (C-Codes)
"C codes" refer to chassis-related diagnostic trouble codes. These codes relate to issues with a vehicle's chassis systems, such as the ABS (anti-lock braking system), traction control system, and other related systems.
Chassis-related diagnostic trouble codes typically start with the letter "C" followed by four digits. For example, C1234 is a common code for an issue with the ABS wheel speed sensor circuit, while C0561 may indicate an issue with the traction control system.
Network Communication Codes (U-Codes)
"U codes" refer to network communication-related diagnostic trouble codes. These codes relate to issues with a vehicle's communication networks, such as the Controller Area Network (CAN) or the Local Interconnect Network (LIN), that are used to exchange data between various modules and systems in the vehicle.
Network communication-related diagnostic trouble codes typically start with the letter "U" followed by four digits. For example, U0100 is a common code for a lost communication issue with the engine control module, while U0155 may indicate a lost communication issue with the instrument cluster module.