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P0516 – Battery Temperature Sensor Circuit Low (OBD2)

P0516 means "Battery Temperature Sensor Circuit Low". The voltage the control unit measures in the charging system circuit is below the permitted minimum. For a sensor this usually means the signal wire is shorted to ground or the reference voltage is missing; for an actuator, that its control wire is shorted to ground.

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P0516 quick summary

Fault codeP0516
MeaningBattery Temperature Sensor Circuit Low
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityHigh
Can I drive?Only briefly. With low charging voltage the battery drains and the engine can stop; with high voltage electronics can be damaged. Have it checked immediately.
Repair cost€0 – €600

How the charging system is monitored

The alternator charges the battery and powers the electrical system while the engine runs; these codes mean the system voltage, the alternator control or the battery temperature sensor is out of range.

A healthy charging system holds the system voltage at about 13.8–14.8 V with the engine running. Many modern cars control the alternator output electronically (smart charging) depending on battery state, temperature and load, using a battery sensor on the negative terminal and an alternator control signal.

Codes P0560–P0563 report that system voltage is faulty, unstable, too low or too high; P0620–P0626 cover the alternator's control, field and lamp circuits; P0514–P0517 the battery temperature sensor.

Low voltage causes starting problems and many random fault codes in other modules; high voltage can damage electronics and boil the battery. Worn alternator brushes and regulators, slipping belts, bad grounds and ageing batteries are the usual causes.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 16900 (P0516). Both numbers mean the same fault.

Symptoms of P0516

  • Battery warning light on
  • Slow cranking or no start
  • Dim or flickering lights
  • Many random fault codes in different modules
  • Battery smell or swelling (overcharging)

Most common causes of P0516 (most likely first)

Mechanic's Pro Tip

After replacing a battery on many modern cars, register it with a scan tool. Otherwise the smart charging system keeps charging it like the old battery, which shortens its life and can bring charging codes back.

  1. 1.Signal or control wire shorted to ground

    Most likely

    Look for chafed insulation where the harness touches the engine, exhaust brackets or body edges.

  2. 2.Missing 5 V reference or supply voltage

    An open reference wire or a shorted sensor elsewhere on the same reference circuit can pull it down.

  3. 3.Internal short in the charging system

  4. 4.Worn alternator regulator or brushes

  5. 5.Weak or failed battery

  6. 6.Loose or corroded battery terminals or ground straps

  7. 7.Slipping or worn drive belt

Step-by-step diagnostic guide

  1. 1

    Measure the battery and charging voltage

    Measure the battery voltage with the engine off and with it running at idle and at 2,000 rpm.

    Multimeter: Engine off: about 12.4–12.7 V. Engine running: about 13.8–14.8 V (smart charging systems may vary between about 12.5 and 15 V).

  2. 2

    Measure the signal voltage

    With the ignition on and the charging system plugged in, back-probe the signal wire. Then unplug it and check the reference/supply and ground wires separately.

    Multimeter: Signal near 0 V = short to ground or no reference. Reference wire: about 5 V with ignition on. Signal wire to ground with connector unplugged: no continuity.

  3. 3

    Load-test the battery

    Test the battery with a proper tester; a weak battery can make a good alternator look bad.

  4. 4

    Check terminals, grounds and belt

    Clean and tighten terminals, check the engine and body ground straps and inspect the drive belt and tensioner.

  5. 5

    Measure voltage drop

    Measure voltage drop on the positive and ground cables while the alternator is loaded.

    Multimeter: Each side should drop less than about 0.3 V under load.

  6. 6

    Check alternator control and battery sensor

    Check the alternator control signal and battery sensor with the scan tool; replace the alternator or regulator if output is wrong.

Frequently asked questions

Can I keep driving with P0516?

Only briefly. With low charging voltage the battery drains and the engine can stop; with high voltage electronics can be damaged. Have it checked immediately.

How much does it cost to fix P0516?

Typical repair costs are 0 € – 600 €, depending on the cause and the vehicle. The most common fixes are: signal or control wire shorted to ground; missing 5 V reference or supply voltage; internal short in the charging system. Always confirm the cause with the tests above before buying parts.

Can a bad battery cause charging system codes?

Yes. A battery with an internal fault can pull the system voltage down or make it unstable.

How long can I drive with the battery light on?

Only until the battery is empty – often less than an hour. Turn off unnecessary consumers and head to a workshop.

What is the difference between P0516 and similar codes?

P0516 belongs to a group of codes for the same component that differ in the type or location of the fault: P0514 – Battery Temperature Sensor Circuit Range/Performance; P0515 – Battery Temperature Sensor Circuit; P0517 – Battery Temperature Sensor Circuit High; P0560 – System Voltage Malfunction; P0561 – System Voltage Unstable; P0562 – System Voltage Low. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.