What Does P0ACD Mean?
The hybrid battery temperature sensor "C" circuit voltage is above the expected maximum threshold. This high-voltage condition typically points to an open circuit in the sensor or its wiring, causing the signal line to float up to reference voltage. The BMS loses accurate thermal data for that battery zone, which can compromise thermal protection strategies.
Common Causes
30%
Open circuit in sensor "C" signal or ground wire
28%
Failed temperature sensor with open internal element
22%
Disconnected or backed-out connector pin
12%
Broken solder joint or wire at the sensor terminal
8%
BMS reference voltage circuit supplying excessive voltage
Diagnostic Steps
1
Read live sensor "C" voltage on the scan tool; confirm it is pegged near 5V reference voltage, indicating an open circuit condition.
2
Inspect the sensor "C" connector at the battery pack for backed-out pins, broken locking tabs, or an unseated connector.
3
Measure continuity from the BMS connector pins to the sensor connector pins for both signal and ground wires; an open reading identifies the broken wire segment.
4
Disconnect the sensor and measure its resistance; an infinite or out-of-range reading confirms an open sensor element.
5
If wiring and sensor test good, measure the BMS reference voltage output and ground integrity at the sensor connector to rule out a module-side fault.
Estimated Repair Cost
$120 - $550
Parts + labor, varies by vehicle and location
The hybrid battery temperature sensor "C" circuit voltage is above the expected maximum threshold. This high-voltage condition typically points to an open circuit in the sensor or its wiring, causing the signal line to float up to reference voltage. The BMS loses accurate thermal data for that batte...
The most common cause of P0ACD (Hybrid Battery Temperature Sensor "C" Circuit High) is: Open circuit in sensor "C" signal or ground wire
Typical repair costs for P0ACD range from $120 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of temperature monitoring in one battery zone means the BMS cannot detect localized overheating. This may lead to undetected thermal stress, accelerated cell degradation, or in worst case, a thermal event. The vehicle will likely limit power output as a protective measure.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0ACD 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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