P0515 – Battery Temperature Sensor Circuit

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

Definition source: SAE J2012/J2012DA (industry standard)

P0515 is a powertrain diagnostic trouble code that indicates a fault detected in the battery temperature sensor circuit. In plain terms, the control module has determined that the electrical signal path associated with battery temperature sensing is not behaving as expected electrically, rather than confirming a battery or charging component has failed outright. How the sensor is packaged (standalone sensor, integrated into a battery monitoring device, or part of a battery assembly) and how the monitoring strategy runs can vary by vehicle, so always verify connector locations, pinouts, and test specifications in the correct service information. Treat P0515 as a circuit-level problem until testing proves a specific component is at fault.

What Does P0515 Mean?

P0515 means the vehicle has detected a problem in the Battery Temperature Sensor Circuit. Based strictly on the official definition, this DTC is set when the control module sees an electrical fault condition related to the circuit used to measure battery temperature. The code points you toward diagnosing the sensor’s signal circuit and its supporting wiring, power, ground, and module input path. SAE J2012 defines how DTCs are structured and categorized, but the exact sensor location, circuit design, and the enable conditions for the monitor (when it runs and what it checks) vary by vehicle and must be confirmed with service information.

Quick Reference

• Subsystem: Battery temperature sensor circuit (battery temperature input to the control module)
• Common triggers: Open/shorted wiring, poor connector contact, corrosion, damaged harness, sensor internal fault, or unstable power/ground affecting the circuit
• Likely root-cause buckets: Wiring/connector issues; sensor fault; power/ground integrity problems; module input/circuit issues (less common)
• Severity: Typically low to moderate; may affect charging strategy and battery management more than immediate driveability
• First checks: Visual inspection of sensor/harness, connector fit/corrosion, battery area damage, and scan-tool data plausibility for battery temperature
• Common mistakes: Replacing the battery or alternator first, ignoring connector pin fit/corrosion, or skipping circuit integrity tests and relying only on code reading

Theory of Operation

The battery temperature sensor provides a temperature-related electrical signal so the control module can adjust battery charging and electrical system management. Depending on design, the sensor may be a thermistor-based device whose resistance changes with temperature, read by a module through a reference feed and a signal return, or it may be part of a battery monitoring assembly that transmits a conditioned signal. The module interprets this input as battery temperature and uses it to manage charging behavior and protection strategies.

P0515 sets when the module detects an electrical problem in the battery temperature sensor circuit, such as an unexpected signal behavior caused by opens, shorts, high resistance, poor connections, or an internal sensor fault. Some vehicles run continuous rationality checks while others evaluate the circuit during specific operating conditions; confirm the monitor’s criteria and circuit layout with service information.

Symptoms

• Warning light: Check Engine Light illuminated
• Charging behavior: Charging system control may be less optimal, potentially leading to undercharging or overcharging tendencies depending on strategy
• Electrical accessories: Accessory performance may be inconsistent if system voltage management is affected
• Battery service messages: Battery/charging or electrical system warnings may appear on some platforms
• Stored codes: Additional battery/charging-related DTCs may accompany P0515 depending on how the system cross-checks inputs
• Intermittent concern: Symptoms may come and go with vibration, temperature changes, or moisture if a connection issue exists

Common Causes

• Open circuit in the battery temperature sensor signal wire (broken conductor, pulled terminal, or poor crimp)
• Short to ground or short to power on the battery temperature sensor circuit due to chafed wiring or contact with metal/brackets
• High resistance in the circuit from corrosion, moisture intrusion, or terminal fretting at the sensor or module connector
• Loose, partially seated, or damaged connector at the battery temperature sensor (including poor pin fit)
• Power supply or ground issue affecting the sensor circuit reference/return path (varies by vehicle wiring design)
• Battery temperature sensor internally failed (biased or unstable signal relative to actual temperature)
• Control module connector issue (bent pins, spread terminals) causing intermittent circuit integrity problems
• Control module fault (driver/input circuit issue) after all circuit and sensor checks pass

Diagnosis Steps

Tools that help include a scan tool with live data and freeze-frame access, a digital multimeter, and basic back-probing leads. Use the correct wiring diagram and connector views from service information (pin IDs and expected behavior vary by vehicle). If available, use a safe heat/cool source for functional checks, and have electrical contact cleaner and terminal inspection tools for connector evaluation.

1. Confirm DTC P0515 is present and record freeze-frame data and any related codes. If other battery/charging or reference/ground codes are stored, address those first because they can corrupt sensor circuit readings.
2. Clear codes and perform a short key-on and engine-running check while viewing live data related to battery temperature (naming varies by scan tool). Note whether the reading is missing, erratic, or implausible, and whether the DTC resets immediately or only after driving.
3. Perform a thorough visual inspection of the battery temperature sensor and its harness routing. Look for pinch points, abrasion, recent battery service disturbance, corrosion at connectors, and any harness segments that can move or rub.
4. Key off. Disconnect the battery temperature sensor connector and inspect both sides for bent pins, pushed-out terminals, spread terminal tension, water intrusion, and green/white corrosion. Repair terminal fitment issues before continuing.
5. With the sensor disconnected, check the harness side for proper power/reference and ground/return integrity per service information. Use a multimeter to verify the circuit is not open and is not shorted to ground or power; exact pin functions and test method vary by vehicle.
6. Check for shorts between the sensor signal circuit and adjacent circuits. Measure continuity between signal and ground, and signal and power feeds with the circuit powered down as directed by service information; any unexpected continuity suggests chafing or melted insulation.
7. Perform a voltage-drop test on the ground/return path (and power/reference feed if applicable) while the circuit is loaded per service information. Excessive drop indicates high resistance from corrosion, damaged wiring, or poor terminal contact that can trigger a circuit fault.
8. Test the sensor itself according to service information. Depending on design, this may be a resistance check or a scan-tool observed response test. Gently warm and then cool the sensor (without exceeding safe temperatures) and confirm the signal changes smoothly rather than jumping or dropping out.
9. Reconnect everything and perform a wiggle test: with live data displayed, gently move the harness near the sensor, battery tray area, and any connectors/junctions in the circuit. If the reading spikes, drops out, or the code resets, isolate the exact movement point and repair the affected section.
10. If circuit integrity and sensor behavior test good, check module-side connector condition and pin fit, and verify the circuit from sensor connector to module connector end-to-end for continuity and insulation integrity. Only after wiring and connector checks pass should a control module fault be considered.
11. After repairs, clear codes and perform a verification drive cycle or monitor run as specified in service information. Recheck for pending codes and confirm live data is stable and plausible across different operating conditions.

Professional tip: Intermittent P0515 faults are often caused by high resistance or poor terminal tension rather than a fully open wire. If the code is hard to reproduce, focus on connector pin fit and voltage-drop testing under load, and use live-data logging during a road test to capture brief dropouts that a quick idle check can miss.

Possible Fixes & Repair Costs

Repair costs for P0515 vary widely because the fault is circuit-related and the correct fix depends on test results, sensor location, harness routing, corrosion extent, and labor access. Confirm the electrical cause before replacing parts to avoid repeat repairs.

• Repair wiring damage: Restore any chafed, broken, pinched, or heat-damaged conductors in the battery temperature sensor circuit using appropriate splices and sealing methods.
• Clean and secure connectors: Remove corrosion, repair terminal tension issues, and ensure connectors are fully seated and locked at the sensor and control module ends.
• Address power/ground issues: Restore shared sensor reference and ground integrity if voltage-drop testing indicates excessive resistance in feeds, grounds, or splice points.
• Replace the battery temperature sensor: Replace only after circuit checks confirm correct reference/ground and an abnormal or unstable sensor response.
• Correct routing and retention: Re-route and re-clip the harness away from sharp edges and moving parts to prevent repeat opens/shorts and intermittent contact.
• Module-level remedy (when proven): If all circuit and sensor tests pass but the fault persists, follow service information for module connector pin-fit checks and any required control-module programming or replacement steps (varies by vehicle).

Can I Still Drive With P0515?

Often the vehicle may still be drivable with P0515, but the risk depends on how the control system uses battery temperature input (varies by vehicle). If you notice starting problems, charging warnings, multiple electrical faults, reduced power, or any safety-related warnings affecting braking or steering, do not continue driving and have the circuit diagnosed promptly.

What Happens If You Ignore P0515?

Ignoring P0515 can lead to improper battery charging behavior because the control module may substitute a default value or limit charging when it cannot trust the battery temperature sensor circuit. Over time this can contribute to repeated warning lights, battery drain or overcharging tendencies, intermittent no-start conditions, and additional diagnostic trouble codes tied to charging or power management.

Related Sensor Battery Codes

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

• P0E0D – Hybrid/EV Battery Energy Control Module Internal Temperature Sensor Circuit
• P0535 – A/C Evaporator Temperature Sensor Circuit
• P0517 – Battery Temperature Sensor Circuit High
• P0516 – Battery Temperature Sensor Circuit Low
• P0514 – Battery Temperature Sensor Circuit Range/Performance
• P0666 – PCM/ECM/TCM Internal Temperature Sensor Circuit

Key Takeaways

• P0515 is a circuit fault: It indicates the battery temperature sensor circuit is not behaving electrically as expected, not a confirmed battery or alternator failure.
• Verify wiring first: Connector corrosion, terminal fit issues, and harness damage are common and should be tested before replacing components.
• Use test-driven diagnosis: Confirm reference, ground integrity, and signal stability with proper electrical checks and live-data review per service information.
• System impact varies: Charging strategy and drivability effects depend on vehicle design and fail-safe logic.
• Fix the root cause: Repairs should match the proven failure mode to prevent comebacks and repeat codes.

Vehicles Commonly Affected by P0515

• Vehicles with battery temperature-based charging control: Systems that adjust charge rate using battery temperature feedback.
• Platforms with remote-mounted batteries: Longer harness runs increase exposure to abrasion, moisture intrusion, and connector issues.
• Vehicles with high underhood heat exposure: Heat can accelerate insulation cracking and terminal relaxation.
• Vehicles operated in corrosive environments: Road salt and humidity can promote connector and splice corrosion.
• Vehicles with recent battery service: Unseated connectors, pinched wiring, or disturbed harness clips after maintenance.
• Vehicles with frequent short trips: Higher electrical demand and charging management activity may reveal marginal circuit faults.
• High-accessory-load configurations: Heavy electrical loads can increase sensitivity to charging management and related sensor inputs.
• Higher-mileage vehicles: Age-related harness brittleness and connector wear can contribute to intermittent circuit faults.

FAQ

Is P0515 telling me the battery is bad?

No. P0515 indicates a fault in the battery temperature sensor circuit. A weak battery can coexist with this code, but the DTC itself points to an electrical circuit/signal issue that must be confirmed with testing.

Can a loose connector cause P0515?

Yes. A partially seated connector, poor terminal tension, corrosion, or a damaged lock can create intermittent opens or high resistance that disrupts the battery temperature sensor circuit and triggers P0515.

Should I replace the battery temperature sensor first?

Not as a first step. Because P0515 is a circuit-related code, verify reference supply, ground quality, and signal continuity/stability at the sensor connector and along the harness before replacing the sensor.

Will clearing P0515 fix the problem?

Clearing the code only resets the diagnostic status. If the underlying circuit fault remains, the monitor will typically fail again and P0515 will return after the relevant self-tests run.

What tests best confirm the cause of P0515?

Start with a thorough visual inspection, then confirm power/ground integrity with voltage-drop testing, verify continuity and isolation on the signal path, and review live data for an implausible or unstable temperature reading while performing a harness wiggle test, following service information for the specific vehicle.

Before any parts replacement, base the repair on verified electrical test results and confirm the fix by clearing the code and completing the appropriate drive cycle or monitor run per service information.