What Does P0ACA Mean?
DTC P0ACA indicates a general circuit malfunction in the 'C' hybrid battery temperature sensor. This is an additional temperature monitoring point in the battery pack, providing thermal coverage of a third zone or module group. A circuit fault here means the BMS has lost temperature monitoring at this location and must rely on interpolation from other sensors or default values.
Common Causes
30%
Faulty battery temperature sensor 'C' (NTC thermistor failure)
26%
Damaged or corroded connector at the 'C' temperature sensor
22%
Open or short circuit in the sensor wiring within the battery enclosure
12%
Poor thermal bonding between sensor and battery module
10%
Battery management system temperature input circuit fault
Diagnostic Steps
1
Read all battery temperature sensor values on the scan tool with the vehicle cold-soaked. Identify the 'C' sensor reading and compare it to other sensors. All should be within 2-3°F of ambient temperature.
2
Locate the 'C' temperature sensor on the battery pack. It may be on a different module group than the 'A' and 'B' sensors. Inspect the sensor and connector for physical damage, corrosion, or displacement.
3
Measure the 'C' sensor resistance with a DVOM and compare to the manufacturer's NTC resistance-temperature specification. The reading should correspond to the current ambient temperature.
4
Verify the reference voltage and ground are present at the sensor connector. Use back-probing or breakout connectors to avoid damaging the terminals.
5
Check wiring continuity between the 'C' sensor and the BMS. Inspect for chafing, pinching, or heat damage along the harness route inside the battery enclosure.
6
If all electrical tests pass, check for a BMS software update or TSB related to temperature sensor monitoring thresholds.
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
DTC P0ACA indicates a general circuit malfunction in the 'C' hybrid battery temperature sensor. This is an additional temperature monitoring point in the battery pack, providing thermal coverage of a third zone or module group. A circuit fault here means the BMS has lost temperature monitoring at th...
The most common cause of P0ACA (Hybrid Battery Temperature Sensor "C" Circuit) is: Faulty battery temperature sensor 'C' (NTC thermistor failure)
Typical repair costs for P0ACA range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Each battery temperature sensor covers a specific zone of the pack. Loss of the 'C' sensor creates a thermal monitoring blind spot that could allow localized overheating to go undetected. On battery packs with limited sensor coverage, each sensor is critical for ensuring safe thermal management.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0ACA to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid Battery Thermal Management
Difficulty
Type
Generic (SAE)
Recommended Tools
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