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 has detected a problem with the sensor that measures the temperature of the coolant used for heating. It's saying the temperature reading is too high.
The P1D64 code is triggered when the Engine Control Module (ECM) detects a high voltage signal from the A/C coolant heater coolant temperature sensor circuit, indicating a higher than expected temperature reading.
The A/C coolant heater coolant temperature sensor is responsible for measuring the temperature of the coolant used in the air conditioning system's heater. A 'high' circuit condition means the sensor is sending a signal indicating a temperature that is higher than the normal operating range. This could be due to a malfunctioning sensor, wiring issues, or a problem with the ECM.
• Check Engine Light illuminated
• Poor heating performance
• A/C system not functioning properly
• Faulty coolant temperature sensor
• Wiring issues such as shorts or open circuits
• Faulty Engine Control Module (ECM)
ECM: Engine Control Module
A/C: Air Conditioning
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the coolant temperature sensor for proper operation.
• Replace the faulty coolant temperature sensor.
• Repair or replace damaged wiring or connectors.
• Replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Honda Accord
• Acura MDX
• Honda Civic
• Regular maintenance checks
• Ensure proper coolant levels
• Inspect wiring periodically
Sensor Issue
• Do not ignore the Check Engine Light.
• Have your vehicle inspected by a professional if unsure.
Check with your vehicle manufacturer for warranty coverage on sensors and ECM.
This code is often associated with vehicles that have aging sensors or wiring issues due to wear and tear.
Moderate – It should be addressed soon to avoid further issues with the A/C system.
Driving with a malfunctioning sensor can lead to improper vehicle operation. Always ensure your vehicle is safe to drive.
• Engine at operating temperature
• A/C system activated
The coolant temperature sensor is typically located near the thermostat housing or along the coolant line.
Q: Can I drive with a P1D64 code?
A: It's possible to drive, but it's not recommended as it may affect your A/C system's performance.
Q: How do I reset the Check Engine Light?
A: After repairs, use an OBD-II scanner to clear the code. If the issue is fixed, 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.