Code P0514 indicates that the powertrain control module has detected a battery temperature sensor reading that is outside the expected range or does not correlate properly with other sensor data. The battery temperature sensor is typically a thermistor that helps the PCM regulate charging voltage based on battery temperature. An out-of-range signal can cause incorrect charging system behavior.
The thermistor sensor itself has drifted out of calibration or failed internally, producing a resistance value that does not correspond to actual battery temperature. This is the most common cause of a range/performance code for this circuit.
Corroded, bent, or loose terminals at the sensor connector, or chafed and shorted wiring between the sensor and the PCM, can alter the resistance reading and trigger a range/performance fault.
If the sensor has become dislodged from its intended mounting location or is sitting against a hot component, it may report a temperature the PCM considers implausible for battery conditions.
Water or coolant entering the sensor connector can create a parallel resistance path, skewing the thermistor reading without setting a hard open or short code.
Internal failure of the PCM's sensor input circuit is extremely rare for this code and should only be considered after the sensor, wiring, and connector have all been verified good with direct measurement.
In most cases the vehicle remains drivable, but the charging system may not regulate voltage correctly, which over time can shorten battery life or cause overcharging. Have it diagnosed at your earliest convenience.
A degraded battery itself does not directly cause P0514, since the code relates to the temperature sensor circuit rather than battery state of charge. However, chronic overcharging caused by a faulty sensor reading can damage the battery over time.
No. PCM failure is very rarely the cause of this code. The sensor and wiring are responsible for the vast majority of P0514 faults. Replacing the PCM without proving the sensor and harness are good is almost always an unnecessary and incorrect repair.
It is typically mounted on or near the battery tray, sometimes attached to the battery case or integrated into the battery monitoring harness. Exact location varies by vehicle, so consult the service information for your specific model.