What Does P0ACE Mean?
The hybrid battery temperature sensor "C" circuit is exhibiting intermittent or erratic signal behavior. The BMS is detecting voltage spikes, dropouts, or inconsistent readings that do not correlate with actual thermal conditions. This is often caused by a loose connection or degraded wiring that makes and breaks contact under vibration or thermal cycling.
Common Causes
35%
Loose or worn sensor connector with intermittent contact
25%
Chafed or cracked wire insulation causing intermittent short or open
20%
Corroded connector terminals with variable contact resistance
12%
Failing temperature sensor with intermittent internal element
8%
Poor ground connection at the BMS or sensor causing signal noise
Diagnostic Steps
1
Monitor sensor "C" live data on the scan tool during a test drive over varied road surfaces; note if signal dropouts correlate with bumps or vibration.
2
Perform a wiggle test on the sensor "C" connector and wiring harness while monitoring live data to try to reproduce the intermittent fault.
3
Inspect the connector for spread or corroded terminals; check the connector locking mechanism for proper engagement.
4
Examine the wiring harness routing through the battery pack for areas of abrasion, sharp bends, or heat damage that could cause intermittent contact.
5
If the fault cannot be reproduced through wiring, replace the sensor as the internal element may have a hairline fracture that fails under thermal stress.
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The hybrid battery temperature sensor "C" circuit is exhibiting intermittent or erratic signal behavior. The BMS is detecting voltage spikes, dropouts, or inconsistent readings that do not correlate with actual thermal conditions. This is often caused by a loose connection or degraded wiring that ma...
The most common cause of P0ACE (Hybrid Battery Temperature Sensor "C" Circuit Intermittent/Erratic) is: Loose or worn sensor connector with intermittent contact
Typical repair costs for P0ACE range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Intermittent temperature data can cause unpredictable BMS behavior, including sudden power derating during acceleration. The erratic readings make it difficult for the system to maintain proper thermal management, which could mask a genuine overheating condition.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0ACE 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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