Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is having trouble getting a steady reading from one of the sensors that checks how hot the battery in a hybrid or electric car is. It's like when a thermometer keeps changing its reading, even though the temperature is the same.
The vehicle's control module detects an inconsistent or erratic signal from the battery temperature sensor, which monitors the temperature of the hybrid/EV battery pack.
The P0C91 code is triggered when the powertrain control module (PCM) or battery management system (BMS) detects an intermittent or erratic signal from the battery temperature sensor labeled 'J'. This sensor is responsible for monitoring the temperature of the hybrid or electric vehicle's battery pack to ensure it operates within safe limits.
• Check Engine Light illuminated
• Reduced fuel efficiency
• Possible battery overheating
• Faulty battery temperature sensor
• Wiring issues or poor connections in the sensor circuit
• Faulty battery management system
PCM: Powertrain Control Module
BMS: Battery Management System
• Use an OBD-II scanner to confirm the code.
• Inspect the battery temperature sensor and its wiring for damage.
• Test the sensor's resistance and compare it to specifications.
• Replace the faulty battery temperature sensor.
• Repair or replace damaged wiring or connectors.
• Update or reprogram the battery management system if necessary.
• OBD-II scanner
• Multimeter
• Wiring repair tools
$100 to $300
Moderate
• Toyota Prius
• Chevrolet Volt
• Nissan Leaf
• Regularly inspect and maintain battery connections.
• Ensure proper cooling of the battery pack.
• Use the vehicle within recommended operating conditions.
Sensor Issue
• Avoid driving the vehicle aggressively until the issue is resolved.
• Monitor the vehicle for any unusual behavior or warnings.
Battery and related components may be covered under the vehicle's hybrid/EV warranty.
This code has become more common with the increased use of hybrid and electric vehicles, highlighting the importance of battery management systems.
Moderate – Should be addressed soon to prevent potential battery damage.
Ignoring this issue could lead to battery damage or reduced vehicle performance.
• Vehicle at normal operating temperature
• Battery under load conditions
The battery temperature sensor is typically located within or near the hybrid/EV battery pack.
Q: Can I drive with the P0C91 code?
A: It's not recommended to drive for extended periods with this code, as it could lead to battery overheating.
Q: How do I reset the P0C91 code?
A: After repairs, use an OBD-II scanner to clear the code. If the issue persists, further diagnosis is needed.
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