Battery Temperature Sensor Circuit
The battery temperature sensor tells your engine computer how hot or cold the battery is, similar to taking your battery's temperature with a thermometer. When this sensor fails or disconnects, the ECU can't properly manage charging and battery protection, triggering this fault code.
The ECU monitors the battery temperature sensor voltage to detect battery temperature and adjust charging voltage accordingly. The sensor typically operates within a specific voltage range that corresponds to temperature thresholds. If voltage is out of range or missing, the ECU logs a circuit fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Voltage | 0.5V to 4.5V (corresponding to -40°C to 125°C) | Below 0.1V or above 4.9V, or no signal detected |
| Temperature Range | -40°C to 65°C typical operating | Signal indicates temperature outside valid range |
Code P0515 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0515 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.