Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
OBDII Code Definition
OBDII DTCs are formatted with a three digit hexadecimal code preceded by an alphanumeric designator. The designator defines the system affected as well as if the code is ISO/SAE or manufacturer controlled.
Body Systems
- B0xxx - ISO/SAE Controlled
- B1xxx - Manufacturer Controlled
- B2xxx - Manufacturer Controlled
- B3xxx - Reserved
Chassis Systems
- C0xxx - ISO/SAE Controlled
- C1xxx - Manufacturer Controlled
- C2xxx - Manufacturer Controlled
- C3xxx - Reserved
Powertrain Systems
- P0xxx - ISO/SAE Controlled
- P1xxx - Manufacturer Controlled
- P2xxx - ISO/SAE Controlled
- P3xxx - Manufacturer Controlled and ISO/SAE Reserved
Network Systems
- U0xxx - ISO/SAE Controlled
- U1xxx - Manufacturer Controlled
- U2xxx - Manufacturer Controlled
- U3xxx - Manufacturer Controlled and ISO/SAE Reserved
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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