Battery Temperature Sensor Circuit Low
The Powertrain Control Module (PCM) uses the battery temperature sensor to adjust the alternator's charging rate based on the physical temperature of the battery. Diagnostic trouble code P0516 is set when the PCM detects that the voltage signal from this sensor circuit has dropped below the minimum expected threshold, typically indicating a short to ground.
While the vehicle will usually remain drivable, an uncorrected battery temperature sensor issue can cause the alternator to overcharge or undercharge the battery. This should be diagnosed soon to prevent premature battery failure or charging system damage.
Common symptoms
- Illuminated Check Engine Light
- Illuminated battery or charging system warning light
- Shorter than normal battery lifespan
- Sulfur or rotten egg smell from an overcharged battery
- Engine cranking slowly due to an undercharged battery
Likely causes
- Short to ground in the battery temperature sensor wiring
- Faulty battery temperature sensor
- Corroded or damaged sensor electrical connector
- Chafed or damaged wiring harness near the battery tray
- Faulty Powertrain Control Module (PCM)
What to check before replacing parts
Inspect the battery temperature sensor, connector, and wiring harness for visible damage or corrosion.
Look for: Bare wires touching metal, broken wires, or green corrosion inside the connector pins.
Disconnect the sensor and measure its internal resistance using a multimeter.
Look for: Resistance values that are out of the manufacturer's specified range for the current ambient temperature, or a dead short (0 ohms).
Disconnect the sensor and the PCM, then test the signal wire for continuity to ground.
Look for: Continuity to ground, which confirms a short circuit in the wiring harness.
Turn the ignition on (engine off) and measure the voltage at the sensor connector's reference wire.
Look for: Approximately 5 volts; if it is significantly lower or zero, there is a wiring issue or PCM fault.
Reconnect the sensor, back-probe the signal wire at the PCM, and monitor the voltage while warming the sensor.
Look for: A smooth change in voltage as temperature changes; if the voltage remains stuck low, the wiring or PCM is at fault.
This page explains the generic P0516 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.