P0517 – Battery Temperature Sensor Circuit High

System: Powertrain | Standard: ISO/SAE Controlled | Fault type: Circuit High

Definition source: SAE J2012/J2012DA (industry standard)

P0517 is a powertrain diagnostic trouble code that indicates the battery temperature sensor circuit is being detected as “high” by a control module. In practical terms, the module is seeing a sensor signal that is higher than the expected electrical range for the current conditions, which commonly points to an electrical issue (such as an open in the signal/return path or a short-to-power) rather than a confirmed battery temperature problem. How the sensor is packaged, where it is located, and what strategy the vehicle uses when the signal is abnormal can vary by vehicle. Always verify the exact circuit layout, connector views, and test specifications in the applicable service information before condemning any parts.

What Does P0517 Mean?

P0517 means Battery Temperature Sensor Circuit High. Per SAE J2012 DTC conventions, this code reports that the module responsible for monitoring the battery temperature sensor input has detected a persistently high electrical signal on that circuit compared with what it considers valid. “Circuit High” is an electrical fault classification: the input is being driven high, pulled high, or is reading high due to a wiring/connection issue, a sensor fault, or a power/ground/reference problem in the measured circuit. The code by itself does not prove the battery is overheating or overcooling; it only confirms the high-input condition was detected.

Quick Reference

• Subsystem: Battery temperature sensor signal circuit (sensor input to the controlling module), including associated reference, signal, and sensor return/ground paths.
• Common triggers: Open circuit in the sensor signal or return, short-to-power on the signal wire, poor connector contact, damaged harness routing, or incorrect reference/ground integrity.
• Likely root-cause buckets: Wiring/connector faults, sensor internal fault, power/ground/reference issues, or less commonly a module input fault (varies by vehicle).
• Severity: Usually moderate; may affect charging strategy and battery management, potentially leading to charging warnings or battery drain concerns.
• First checks: Visual inspection of sensor/connector/harness near the battery area, check for looseness/corrosion, verify secure grounds, and confirm the code is current (not historical) with a scan tool.
• Common mistakes: Replacing the battery or alternator first, assuming an actual temperature problem without circuit testing, or skipping connector pin-fit and ground integrity checks.

Theory of Operation

The battery temperature sensor provides the control module with battery temperature information so charging behavior can be managed appropriately. Depending on design, the sensor may be integrated into the battery monitoring assembly, attached near the battery, or incorporated into a harness. Typically, the sensor changes its electrical characteristic with temperature, and the module interprets that change as a temperature value via a signal circuit that references a sensor return/ground and, in many designs, a dedicated reference supply.

When the monitored input is electrically “high,” the module sees a signal that is higher than the valid operating window for that circuit. This can happen if the signal wire is shorted to a power source, if the sensor return/ground path opens (allowing the signal to float high), or if a connector/harness fault prevents the sensor from properly loading the circuit. After the condition meets the monitor’s enable criteria and fault time/filtering logic (varies by vehicle), the module stores P0517.

Symptoms

• Warning light: Check engine light or malfunction indicator lamp illuminated.
• Charging message: Charging system or battery management warning displayed (if equipped).
• Battery performance: Reduced battery charge retention or unexpected battery discharge due to altered charging strategy.
• Electrical behavior: Intermittent electrical accessory issues if system voltage management is affected.
• Scan data: Battery temperature PID reading implausibly high or pegged at an extreme value.
• Related codes: Additional battery/charging management or sensor circuit codes stored depending on platform strategy.

Common Causes

• Short-to-power on the battery temperature sensor signal circuit (chafed harness contacting a voltage source)
• Open ground on the sensor circuit (broken ground wire, poor ground point, or high resistance in the ground path)
• Open in the sensor signal circuit causing the control module to interpret a high input (broken conductor, loose terminal, poor pin fit)
• Connector problems at the sensor or control module (corrosion, water intrusion, bent pins, terminal push-out, poor engagement)
• High reference/biased feed to the sensor circuit due to wiring damage or incorrect backfeed from another circuit
• Battery temperature sensor internal fault that biases output high (varies by sensor design)
• Harness routing or strain issues leading to intermittent opens/shorts (movement-related faults)
• Control module input circuit concern (less common; verify power/grounds and circuit integrity first)

Diagnosis Steps

Tools typically needed include a scan tool capable of viewing live data and freeze-frame, a digital multimeter, and access to vehicle-specific wiring diagrams and connector pinouts. If available, use back-probing tools, terminal tension tools, and a test light appropriate for low-current signal circuits. Consult service information for the exact circuit type, pin identification, and test specifications.

1. Confirm the DTC and capture freeze-frame data. Note any related powertrain codes that could affect sensor reference, module power, or grounds; address those first if they indicate a shared electrical problem.
2. Check for a consistent fault versus intermittent behavior. Clear the code and perform a short key-on/engine-on check while monitoring the battery temperature sensor parameter(s) in live data to see if the reading immediately appears invalid or spikes high.
3. Perform a thorough visual inspection of the battery temperature sensor area and harness routing. Look for abrasion points, pinch points, prior repairs, contact with hot/moving components, and any signs of fluid intrusion at connectors.
4. Inspect connectors at the sensor and the control module input side (as accessible). Check for bent pins, corrosion, terminal spread, terminal push-out, missing seals, and evidence of overheating. Correct any mechanical fit issues before electrical testing.
5. Wiggle test: with live data displayed, gently move the harness and connectors along the sensor circuit path. If the sensor reading jumps high or the DTC resets, isolate the movement-sensitive section and recheck for poor pin fit, broken strands, or insulation damage.
6. Key off, disconnect the sensor, and verify the circuit is not being driven high by an unintended power source. Using the wiring diagram, test for unexpected voltage on the signal circuit relative to ground. If present, trace for a short-to-power or backfeed from an adjacent circuit.
7. Verify reference feed integrity (if the design uses a reference supply). With the correct pins identified, confirm the reference is present and stable per service information. If the reference is higher than expected or unstable, inspect the reference circuit for shorts to power and check for other sensors sharing that reference.
8. Verify ground integrity with voltage-drop testing. Under key-on conditions (and with the circuit loaded as applicable per service info), measure voltage drop from the sensor ground pin to a known good chassis/engine ground. Excessive drop indicates high resistance in the ground path that can produce a “circuit high” interpretation.
9. Check continuity and resistance of the signal and ground circuits end-to-end (sensor connector to module connector) with both ends disconnected. Look for opens, high resistance, or intermittent continuity when flexing the harness; repair wiring faults found.
10. If wiring and connectors test good, evaluate the sensor itself using the manufacturer’s procedure for that sensor type. If results are out of specification or the sensor output is biased high under controlled conditions, replace the sensor and recheck operation.
11. If the fault persists after verified circuit and sensor integrity, verify control module power and grounds (including voltage-drop under load). Only after confirming stable powers/grounds and clean circuit signals should a module input fault be considered, following service information.

Professional tip: When diagnosing a “circuit high” fault, prioritize proving whether the signal is being pulled high by a short-to-power/backfeed versus being interpreted high due to an open ground or open signal. Logging live data during a controlled wiggle test and performing voltage-drop checks under load often exposes marginal grounds and terminal issues that pass simple continuity tests.

Possible Fixes & Repair Costs

Repair costs for P0517 vary widely because the same “circuit high” condition can be caused by different issues, from a simple connector problem to harness damage. The final cost depends on verified diagnosis results, parts replacement needs, and labor time based on component access.

• Repair wiring faults: Locate and repair opens, rubbed-through insulation, or short-to-power conditions in the battery temperature sensor signal/reference circuits, then secure and re-route the harness as needed.
• Service connectors: Clean contamination, correct poor terminal tension/pin fit, remove corrosion, and ensure connectors are fully seated and locked at the sensor and control module.
• Restore power/ground integrity: Repair shared sensor ground issues, loose ground fasteners, or damaged ground splices; correct power-feed faults affecting the sensor circuit where applicable (varies by vehicle).
• Replace the battery temperature sensor: Replace only after testing confirms the sensor is producing an implausibly high electrical signal or the circuit behaves correctly with a known-good substitute (procedure varies by vehicle).
• Repair harness near heat/movement points: Address recurring faults by protecting sections routed near hot components, sharp edges, battery hold-downs, or moving parts that can intermittently push the signal high.
• Module-side repair: If all circuit checks pass and the high-input condition is verified at the module pins, follow service information for module connector repair or module replacement/reconfiguration (varies by vehicle).

Can I Still Drive With P0517?

Often the vehicle may remain drivable, but P0517 indicates the battery temperature sensor circuit is reading electrically high, which can lead to incorrect charging or battery management decisions. If you notice warning lights related to charging, reduced electrical performance, repeated dead-battery events, or any safety-related symptoms such as stalling, no-start, reduced power, or steering/brake warnings, avoid driving and diagnose the fault promptly. If it drives normally, keep trips short and minimize electrical loads until the issue is confirmed and repaired.

What Happens If You Ignore P0517?

Ignoring P0517 can allow an ongoing circuit high condition to persist, potentially causing improper alternator/regulator control strategies and battery state management (varies by vehicle). Over time this may contribute to charging complaints, reduced battery life, intermittent no-start conditions, or repeated warning lights, and can complicate diagnosis if the wiring damage worsens.

Related Sensor Battery Codes

Compare nearby sensor battery trouble codes with similar definitions, fault patterns, and diagnostic paths.

• P0538 – A/C Evaporator Temperature Sensor Circuit High
• P0516 – Battery Temperature Sensor Circuit Low
• P0515 – Battery Temperature Sensor Circuit
• P0514 – Battery Temperature Sensor Circuit Range/Performance
• P0935 – Hydraulic Pressure Sensor Circuit High
• P0808 – Clutch Position Sensor Circuit High

Key Takeaways

• P0517 is a circuit high code: The fault is an electrically high input in the battery temperature sensor circuit, not proof of a bad battery or confirmed overheating.
• Start with wiring and connectors: Opens, short-to-power, poor terminal fit, and shared ground problems are common and should be tested before replacing parts.
• Verify at the module: Confirm whether the high signal is present at the control module pins to separate sensor/harness issues from module-side concerns.
• Driveability varies: Many vehicles still drive, but charging behavior and battery reliability can be affected depending on design.
• Fix the verified cause only: Use test results to choose the repair, then clear the code and confirm it does not return.

Vehicles Commonly Affected by P0517

• Vehicles with ECU-managed charging: Systems that adjust charging based on sensed battery temperature.
• Vehicles with battery monitoring sensors: Platforms using multiple battery-related inputs for charging and load control (varies by vehicle).
• Vehicles driven in harsh environments: Heat, vibration, or corrosion exposure that can damage connectors or wiring near the battery area.
• High-electrical-load applications: Frequent use of accessories that increases charging system activity and sensitivity to sensor signal faults.
• Vehicles with tight engine-bay packaging: Increased likelihood of harness chafing, pinched wiring, or strain on connectors near the battery.
• Vehicles with recent battery service: Greater risk of disturbed connectors, misrouted harnesses, or partially seated plugs after maintenance.
• Higher-mileage vehicles: Aging insulation, fretting at terminals, and ground point degradation can contribute to circuit high readings.

FAQ

Does P0517 mean the battery is overheating?

No. P0517 means the battery temperature sensor circuit is reporting an electrically high input. That points to an electrical problem such as an open in a pull-down path, a short-to-power, a wiring/connector issue, or a sensor output fault. Confirm the actual battery temperature and verify the circuit with testing.

What is the most common cause of a “circuit high” condition for this code?

The most common causes are wiring and connector faults: an open or high resistance in the signal/ground path that allows the signal to be pulled high, damage to insulation causing a short to a power source, or poor terminal contact. The exact failure mode varies by vehicle design.

Will replacing the battery fix P0517?

Usually not. This DTC is about the battery temperature sensor circuit reading high, not a direct assessment of battery condition. A weak battery can cause charging-related symptoms, but it will not typically correct a circuit high fault unless the real issue is a disturbed connector or wiring problem corrected during battery service.

Can a bad ground cause P0517?

Yes. If the sensor uses a ground reference and that ground is open, loose, or high resistance, the signal can appear electrically high at the control module. Ground integrity should be verified with appropriate circuit testing and voltage-drop checks per service information.

Do I need to replace the control module for P0517?

Not in most cases. Module replacement should be considered only after confirming the wiring, connectors, sensor supply/reference, and grounds are correct, and after verifying the high-input condition is present at the module pins with the sensor and harness proven good. Always follow the vehicle’s service procedures for any module-related repair.

Use service information for your exact vehicle to identify the sensor location, circuit routing, and connector pinouts so you can confirm the “circuit high” condition with targeted testing before replacing any parts.