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 found a problem with a sensor that checks how hot or cold the coolant is in a part of the car that helps keep it cool.
The P0E81 code is triggered when the vehicle's computer detects an issue with the circuit of the auxiliary cooling system's coolant temperature sensor. This sensor helps monitor the temperature of the coolant in the auxiliary cooling system.
The auxiliary cooling system coolant temperature sensor is responsible for monitoring the temperature of the coolant in the auxiliary cooling system. This sensor sends data to the vehicle's computer to ensure the system operates within the optimal temperature range. A fault in the sensor circuit can lead to improper temperature readings, affecting the cooling system's performance.
• Check Engine Light illuminated
• Overheating of the auxiliary cooling system
• Poor vehicle performance
• Faulty coolant temperature sensor
• Wiring issues such as open or short circuits
• Corroded or damaged sensor connectors
Coolant: A fluid that helps keep the engine at the right temperature.
Sensor: A device that detects or measures a physical property and records, indicates, or otherwise responds to it.
• Use an OBD-II scanner to confirm the code
• Inspect the coolant temperature sensor and its wiring
• Check for corrosion or damage in the sensor connectors
• Replace the faulty coolant temperature sensor
• Repair or replace damaged wiring
• Clean or replace corroded connectors
• OBD-II scanner
• Multimeter
• Wrench set
$100 - $300
Moderate
• Toyota Prius
• Chevrolet Volt
• Ford Fusion Hybrid
• Regular maintenance checks
• Ensure coolant levels are adequate
• Inspect wiring for damage periodically
Sensor Issue
• Do not ignore the Check Engine Light
• Have the vehicle inspected by a professional
• Avoid driving the vehicle if overheating occurs
Check with your vehicle manufacturer for specific warranty details on emission-related components.
This code has been associated with hybrid and electric vehicles due to their complex cooling systems.
Moderate – It should be addressed soon to prevent potential overheating issues.
Driving with a malfunctioning cooling system can lead to engine damage and is not recommended.
• Engine running
• Coolant at operating temperature
The auxiliary cooling system coolant temperature sensor is typically located near the auxiliary radiator or cooling components.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to overheating, which may cause engine damage.
Q: Can I drive my car with this code?
A: It's not recommended to drive the vehicle with this code active, especially if overheating occurs.
High-End · Full-system diagnostics
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Network faults often require full-system access instead of a generic code reader alone.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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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.