Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car's computer thinks the temperature sensor for the engine is saying it's super hot, even if it's not. It's like a thermometer that's broken and always says it's boiling outside.
The Engine Coolant Temperature (ECT) sensor is sending a signal to the engine control module (ECM) that is higher than the expected range, indicating a potential issue with the sensor or its circuit.
The P0118 code is triggered when the ECM detects a voltage signal from the ECT sensor that is higher than the specified range. This sensor helps the ECM determine the engine's operating temperature. A high signal could indicate an open circuit, a faulty sensor, or a wiring issue.
• Check Engine Light is on
• Poor fuel economy
• Engine overheating
• Faulty Engine Coolant Temperature sensor
• Poor electrical connection in the ECT sensor circuit
• Open or shorted ECT sensor wiring
ECM: Engine Control Module
ECT: Engine Coolant Temperature
• Use an OBD-II scanner to confirm the P0118 code.
• Inspect the ECT sensor and its wiring for damage.
• Test the ECT sensor resistance and compare it with specifications.
• Replace the Engine Coolant Temperature sensor if faulty.
• Repair or replace damaged wiring or connectors.
• Clear the code and test drive to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Wrench set
$100 - $250
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain the cooling system.
• Check and replace coolant as needed.
• Ensure electrical connections are secure and free of corrosion.
Sensor Issue
• Do not ignore the Check Engine Light.
• Monitor engine temperature to prevent overheating.
Check with your vehicle manufacturer for specific warranty coverage related to emissions and sensors.
The P0118 code has been a common issue with vehicles that have aging cooling systems or poor maintenance practices.
Moderate – Should be addressed to avoid potential engine damage.
Driving with an unresolved P0118 code can lead to engine overheating and potential damage, which may not be covered under warranty.
• Engine at operating temperature
• Stable voltage supply
The Engine Coolant Temperature sensor is typically located near the thermostat housing on the engine block.
Q: Can I drive my car with a P0118 code?
A: It's not recommended to drive for long periods with this code as it can lead to engine overheating.
Q: How do I know if my ECT sensor is bad?
A: Symptoms include poor fuel economy, erratic temperature readings, and the Check Engine Light being on.
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Universal · Digital multimeter
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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.