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 a sensor in the car that checks how hot or cold the battery coolant is, is giving a reading that's too high. It's like a thermometer saying it's really hot, even if it might not be.
The P2E77 code indicates that the voltage signal from the battery pack coolant temperature sensor is higher than the expected range.
The Hybrid/EV Battery Pack Coolant Temperature Sensor D is responsible for monitoring the temperature of the coolant that helps keep the battery pack at an optimal temperature. A 'Circuit High' condition means that the sensor is reporting a voltage higher than the normal operating range, which could be due to a fault in the sensor, wiring issues, or a problem with the control module.
• Check engine light is on
• Possible reduced fuel efficiency
• Potential overheating of the battery pack
• Faulty coolant temperature sensor
• Wiring issues such as shorts or open circuits
• Faulty control module
OBD-II: On-Board Diagnostics, a standardized system in vehicles for self-diagnosis and reporting.
Coolant: A fluid used to regulate temperature in engines and battery systems.
• Use an OBD-II scanner to confirm the code
• Inspect the coolant temperature sensor and wiring for damage
• Test the sensor's voltage output with a multimeter
• Replace the faulty coolant temperature sensor
• Repair or replace damaged wiring/connectors
• Reprogram or replace the control module if necessary
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Toyota Prius
• Chevrolet Volt
• Nissan Leaf
• Regularly inspect and maintain the cooling system
• Check for any wiring damage or corrosion
• Ensure proper coolant levels are maintained
Sensor Issue
• Do not ignore the check engine light; get it diagnosed promptly.
• Regular maintenance can prevent such issues.
• Consult a professional if unsure about repairs.
Check with your vehicle manufacturer for specific warranty coverage related to hybrid/EV components.
As hybrid and electric vehicles have become more common, codes related to battery cooling systems have become more prevalent due to their critical role in vehicle performance.
Moderate – While the vehicle may still operate, ignoring this issue can lead to battery overheating and reduced efficiency.
Driving with a malfunctioning battery cooling system can lead to overheating, which may pose safety risks. Always address such issues promptly.
• Vehicle at operating temperature
• Engine running
The coolant temperature sensor is typically located near the battery pack or within the cooling system of the vehicle.
Q: Can I drive my car with a P2E77 code?
A: It's not recommended to drive for extended periods with this code, as it may lead to battery overheating.
Q: How do I reset the check engine light after fixing the issue?
A: After repairs, use an OBD-II scanner to clear the code. If the issue is resolved, the light should stay off.
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Fitment Required · Vehicle-fitment part
Relevant when coolant-temperature and warm-up faults indicate a thermostat-related issue.
Coolant-temperature and warm-up faults often lead to thermostat testing and replacement.
Thermostats are vehicle-specific and should be matched by engine and housing style.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.