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P0516Battery Temperature Sensor Circuit Low

The battery temperature sensor signal voltage is lower than the normal operating range.

Definition

The PCM feeds a reference voltage to the battery temperature sensor, a thermistor whose signal voltage falls as temperature rises; it uses the reading to trim alternator charging voltage. P0516 sets when the signal voltage drops below the plausible minimum — typically meaning the circuit is shorted to ground or the sensor element has failed shorted, which would falsely indicate an extremely hot battery. The PCM defaults to a fixed charging strategy, so drivers usually notice only the warning lamp, though prolonged default charging can shorten battery life.

Common causes

  • Battery temperature sensor shorted internally
  • Signal wire chafed and shorted to ground
  • Acid-corroded connector creating a path to ground
  • Damaged pigtail under the battery tray
  • PCM input fault (rare)

Common misdiagnoses

  • Alternator
  • Battery
  • Voltage regulator
  • PCM

Troubleshooting steps

  1. 1.Read the battery temperature PID

    A reading pegged at the maximum hot value (often 250 degrees F or more) on a cool engine confirms the signal is pulled low.

  2. 2.Disconnect the sensor and re-check

    Unplug the sensor with the key on; if the reading swings to the extreme cold value, the circuit is intact and the sensor itself is shorted.

  3. 3.Check for a shorted harness

    If the reading stays pegged hot with the sensor unplugged, disconnect the PCM and ohm the signal wire to ground to locate the short, inspecting where the harness passes under the battery tray.

  4. 4.Inspect for acid damage

    Remove the battery and examine the sensor, connector, and wiring for acid corrosion, a very common cause when the battery has leaked.

  5. 5.Replace the sensor or repair wiring

    Install a new sensor or repair the shorted section, then verify a plausible temperature reading and normal charging voltage.

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