What Does P0ACC Mean?
The hybrid battery temperature sensor "C" circuit is producing a voltage signal below the expected minimum threshold. This typically indicates a short to ground in the sensor circuit, a failed sensor with low internal resistance, or an open pull-up reference voltage line. The BMS may substitute a default temperature value, which can lead to inadequate or excessive cooling fan operation.
Common Causes
30%
Short to ground in sensor "C" signal wire
30%
Failed temperature sensor with internally shorted element
20%
Corroded connector allowing moisture-induced low-resistance path
12%
Damaged wiring harness pinched against battery module casing
8%
BMS analog input circuit fault
Diagnostic Steps
1
Read live data for sensor "C" voltage and compare to sensors "A" and "B"; confirm the voltage is abnormally low (near 0V).
2
Disconnect the sensor "C" connector at the battery pack and measure the voltage at the BMS harness side; if voltage rises to reference level, the sensor is shorted internally.
3
With the sensor disconnected, measure sensor resistance; compare to spec at current ambient temperature — an abnormally low reading confirms a failed sensor.
4
Inspect the wiring harness routing through the battery pack for chafing, pinch points, or heat damage that could cause insulation breakdown and a short to ground.
5
Check the connector pins for green corrosion or moisture; clean or replace the connector as needed.
Estimated Repair Cost
$120 - $550
Parts + labor, varies by vehicle and location
The hybrid battery temperature sensor "C" circuit is producing a voltage signal below the expected minimum threshold. This typically indicates a short to ground in the sensor circuit, a failed sensor with low internal resistance, or an open pull-up reference voltage line. The BMS may substitute a de...
The most common cause of P0ACC (Hybrid Battery Temperature Sensor "C" Circuit Low) is: Short to ground in sensor "C" signal wire
Typical repair costs for P0ACC range from $120 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A low signal may cause the BMS to interpret excessively high or low temperatures depending on sensor polarity, potentially masking a real overheating condition. Continued driving without proper thermal monitoring risks battery degradation or safety events.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0ACC 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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