Open circuit or high resistance in the sensor wiring, such as a broken wire or corroded terminal; Faulty battery temperature sensor; Sensor connector unplugged, loose, damaged or contaminated with corrosion; Sensor signal wire shorted to a voltage supply; Fault in the control unit or charging system module that reads the sensor; Damaged battery or battery terminal assembly where the sensor is built into the battery lead or clamp.

P0517

Battery Temperature Sensor Circuit High.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
5: AreaVehicle speed, idle control and auxiliary inputs
17: FaultThe specific fault in that area

What it means

P0517 is the generic code for a Battery Temperature Sensor Circuit High fault. The control unit saw a signal voltage from the battery temperature sensor circuit that was higher than expected, which usually points to an open circuit, a poor connection or a failed sensor. The battery temperature sensor is used to adjust charging voltage, and where it is fitted and how it is wired varies by model.

Symptoms

Battery or charging warning light on, or a check engine light
Battery undercharging or overcharging in cold or hot weather
Flat battery or slow cranking after short journeys
Charging voltage that looks wrong or does not change with temperature
Possible start-stop system not working

Possible causes

Open circuit or high resistance in the sensor wiring, such as a broken wire or corroded terminallikely
Faulty battery temperature sensorlikely
Sensor connector unplugged, loose, damaged or contaminated with corrosionlikely
Sensor signal wire shorted to a voltage supplypossible
Fault in the control unit or charging system module that reads the sensorrare
Damaged battery or battery terminal assembly where the sensor is built into the battery lead or clamppossible

How to diagnose

Read all stored codes and freeze frame data, and note whether the fault is current or intermittent.
Visually inspect the battery temperature sensor, its wiring and connector for damage, corrosion, chafing or poor routing.
Check the battery terminals and earth connections are clean and tight, and test battery condition and charging voltage.
Look at live data for battery temperature and compare it with ambient temperature on a cold car; a stuck extreme reading suggests an open circuit or a failed sensor.
Check the sensor resistance against the manufacturer's specification at a known temperature.
With the connector unplugged and the ignition on, check the reference voltage and the signal wire for a short to voltage using the wiring diagram for that model.
Test the wiring for continuity and resistance between the sensor and the control unit, and check the earth return.
If the wiring and sensor are good, check for software updates and have the control unit tested as a last resort.

How to fix

Repair or replace damaged wiring and corroded or loose connector terminals.
Replace the battery temperature sensor, which on some models is part of the battery lead or terminal clamp.
Reseat and secure the connector, and clean any corrosion.
Repair any short to voltage in the sensor circuit.
Replace or reprogram the control unit only after the circuit and sensor are proven good, and only where the manufacturer lists it as a fix.

Can I keep driving?

Low severity

The car can normally be driven, but charging control may be less accurate, so watch battery condition and book it in soon. If the battery warning light comes on or the car struggles to start, get the charging system checked promptly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.