Symptoms of P0514
- Unstable, high, or low idle, or stalling.
- Erratic speedometer, cruise-control, or shift behaviour.
- Check-engine light with a hesitation or surge.
Common causes of P0514
- A dirty throttle body, idle-control valve, or throttle-position sensor.
- A failing vehicle-speed or wheel-speed sensor, or its wiring.
- Vacuum leaks or a related sensor forcing the idle/speed strategy.
Useful checks before replacing parts
- Compare battery temperature data to ambient temperature, intake air temperature, battery voltage, charging command, freeze-frame data, and related charging codes.
- Inspect sensor placement, connector condition, wiring resistance, corrosion at battery area, reference voltage, ground, and battery acid damage.
- Check whether the signal is biased, slow, noisy, or implausible during cold soak and warm operation.
Related OBD-II codes
These nearby speed / idle entries can help compare wording and pin down the fault area.