Diagnostic Terms
Technical concepts used in OBD, measurement and troubleshooting.
Related records are ordered by brand and name.
ABS
A system controlling brake pressure to reduce wheel lock.
Electronic Stability Control
A system intervening in braking and engine torque to support directional stability.
OBD-II
A standardised framework for accessing vehicle emissions and powertrain diagnostic information.
Traction Control System
A system limiting excessive slip at driven wheels.
Misfire
A condition where expected combustion energy is not produced in one or more cylinders.
Open Circuit
A circuit condition in which the electrical current path is broken or incomplete.
Pending trouble code
A code for a fault condition observed before permanent confirmation criteria are met.
Pending DTC
A code whose fault condition has been detected but confirmation criteria are not yet complete.
Live data
Parameters read from a control unit in real or near-real time.
Freeze-frame Data
A snapshot of selected operating values captured when a DTC is stored.
Readiness Monitor
A record indicating completion status of specific OBD emissions tests.
Permanent trouble code
A code class retained until the system verifies that an emissions-related repair is effective.
Permanent DTC
An OBD record retained until the relevant system verifies that the fault has been resolved.
Limp Mode
An operating strategy limiting performance after a fault to reduce damage or safety risk.
Short-term fuel trim
A rapid fuelling correction responding to oxygen-sensor feedback.
Implausible Signal
A signal that is electrically present but inconsistent with other values or operating conditions.
Long-term fuel trim
A slower learned fuelling adaptation responding to persistent trends.
Fuel Trim
Fuel adjustment applied by a control unit to reach the target air-fuel ratio.
Short to Ground
A condition in which a signal or supply line is unintentionally connected to low potential.
Move from vehicle class to technical system
After choosing brand and model identity, use engine, transmission, DTC, electronics and service guidance in the same technical context.
Sources & freshness
Exact technical values, prices and failure rates are not invented without verified vehicle/manufacturer evidence.