Battery Temperature Sensor Circuit
P0515 indicates the engine control module detected a fault in the battery temperature sensor circuit, which monitors battery temperature to optimize charging voltage and protect the battery. This code sets when the sensor signal is outside expected parameters, typically due to electrical faults or sensor damage.
What You Might Notice
- Check Engine light illuminated
- Low or incorrect charging voltage reading
- Charge indicator light on dashboard
- Battery not charging properly
- Intermittent electrical issues
Most Common Causes
- 1
Battery Temperature Sensor Failure
The BTS sensor itself may be damaged, corroded, or have failed internally, causing it to send an out-of-range signal to the ECU.
- 2
Open Circuit in Sensor Wiring
A break, disconnection, or corrosion in the sensor signal wiring or connector prevents proper communication between the sensor and ECU.
- 3
Short to Voltage in Signal Circuit
The sensor signal wire may be shorted to positive voltage, causing the ECU to receive an invalid high signal reading.
- 4
ECU or Connector Issues
A faulty connector at the sensor or ECU end, or a defective engine control module, may prevent proper signal reception.
How to Diagnose It
- 1
Check Battery Temperature Sensor Failure — The BTS sensor itself may be damaged, corroded, or have failed internally, causing it to send an out-of-range signal to the ECU.
- 2
Check Open Circuit in Sensor Wiring — A break, disconnection, or corrosion in the sensor signal wiring or connector prevents proper communication between the sensor and ECU.
- 3
Check Short to Voltage in Signal Circuit — The sensor signal wire may be shorted to positive voltage, causing the ECU to receive an invalid high signal reading.
- 4
Check ECU or Connector Issues — A faulty connector at the sensor or ECU end, or a defective engine control module, may prevent proper signal reception.
How to Fix It
- 1
Inspect and Test Battery Temperature Sensor
Locate the BTS sensor on or near the battery, visually inspect for damage or corrosion, and test its resistance and voltage output with a multimeter against manufacturer specifications.
- 2
Check Sensor Circuit Wiring and Connectors
Inspect the signal wire from the sensor to the ECU for breaks, corrosion, or loose connections; clean or repair connectors as needed and verify wire continuity.
- 3
Replace Battery Temperature Sensor
If testing confirms sensor failure, disconnect the old sensor and install a new one, ensuring proper connection to the battery or mounting location.
- 4
Repair or Replace Wiring and Connectors
If wiring is damaged or corroded beyond cleaning, replace the affected wire segment or connector, then retest the circuit for proper operation.
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