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DTC codes / P0Axx · Hybrid propulsion / P0ACC

P0ACCHybrid/EV Battery Temperature Sensor C Circuit Low

P0ACC indicates that the hybrid or electric vehicle battery pack's temperature sensor C is reporting a voltage below the normal range, which the battery energy control module interprets as a low circuit condition. The computer has detected an abnormally low signal voltage on the sensor C circuit, which can be caused by a short to ground, an open circuit, or a faulty sensor.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light or hybrid system warning light
  • Reduced electric driving range or hybrid system power limitation
  • Battery cooling fan may run continuously or not at all
  • In some cases, the vehicle may enter a fail-safe mode with reduced performance
  • Often no symptoms besides the warning light

Common causes, most likely first

  1. Faulty battery temperature sensor C
  2. Short to ground in the sensor C signal circuit
  3. Open or high-resistance connection in the sensor C circuit
  4. Damaged wiring harness or connector at the sensor or battery pack
  5. Corrosion or water intrusion in the sensor connector
  6. Internal fault in the battery energy control module (BECM)

How to diagnose and fix it

  1. Scan all modules for stored codes and freeze-frame data to confirm P0ACC is current
  2. Visually inspect the sensor C wiring and connector for damage, corrosion, or loose pins
  3. Measure resistance of sensor C and compare to the manufacturer's specification
  4. Check for a short to ground on the signal circuit using a multimeter
  5. Verify continuity and voltage drop on the sensor C circuit from the sensor to the BECM
  6. If wiring and sensor test good, perform a wiggle test on the harness while monitoring sensor data
  7. Replace the faulty sensor or repair the wiring as needed, then clear codes and verify the repair

Sensor C circuit low: common traps

  • A low voltage code often results from a short to ground rather than a failed sensor, so inspect the harness for chafing before replacing parts.
  • The sensor C circuit may share a common ground with other sensors, and a bad ground can set multiple temperature sensor codes simultaneously.
  • Battery pack temperature sensors are sometimes integrated into a single harness inside the pack, making connector inspection at the pack interface critical.
  • A faulty BECM can misinterpret a normal sensor signal, so always verify the sensor and wiring before condemning the module.
  • After repairs, the hybrid system may require a relearn or calibration procedure to clear the code permanently.

Can I keep driving with P0ACC?

It is generally safe to drive with this code if the vehicle is not in a reduced-power mode, but avoid aggressive driving or heavy electrical loads until diagnosed. Prolonged driving with a faulty temperature sensor can lead to battery overheating or damage, so schedule service soon.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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