Diagnostic Trouble Code (DTC)
A diagnostic trouble code is a code stored by a control unit when it detects a fault, such as P0300.
What is Diagnostic Trouble Code (DTC)?
The first letter shows the system: P powertrain, B body, C chassis and U network. Generic codes have the same meaning for all makes; manufacturer-specific codes differ by brand. Codes can be read with an OBD-II scan tool connected to the diagnostic port.
How it works
The control unit runs self-tests; when a test fails under defined conditions, a code is stored and may light a warning lamp.
Why it matters for your car
A code shows where the fault was detected, not always which part is broken. Read freeze frame data and check the basics before replacing parts.
Other terms
- ADAS (Advanced Driver Assistance Systems)
- Car Detailing
- Clutch Judder
- Contact Breaker Points
- Drag Coefficient (Cd)
- Front Grille
- High-voltage Cable (Orange Cable)
- Jockey Wheel
- Lane Departure Warning
- Low Emission Zone (LEZ)
- OEM Parts (Original Equipment)
- Plug & Charge (ISO 15118)
- Regenerative Braking
- Roundabout
- Seatbelt Reminder
- Six-Volt Electrical System
- Snow Socks (Textile Snow Chains)
- Tyre Pressure Placard
- Tyre Repair Kit (Sealant Kit)
- Wading Depth