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 computer in your car found a problem with how the air conditioner's electric compressor and the engine's cooling system are working together. It's like when two friends are supposed to work together, but they're not getting along.
The P1D42 code is triggered when the temperature readings from the electric A/C compressor control module and the engine coolant temperature sensor do not align as expected.
The P1D42 code indicates a discrepancy between the temperature reported by the electric A/C compressor control module and the engine coolant temperature sensor. This could be due to a fault in the sensor readings, wiring issues, or a malfunction in the control module itself.
• Check Engine Light is on
• Air conditioning not working properly
• Engine overheating
• Faulty electric A/C compressor control module
• Faulty engine coolant temperature sensor
• Wiring or connector issues between components
A/C: Air Conditioning
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the code.
• Inspect wiring and connectors for damage or corrosion.
• Test the electric A/C compressor control module and engine coolant temperature sensor.
• Repair or replace damaged wiring or connectors.
• Replace the electric A/C compressor control module if faulty.
• Replace the engine coolant temperature sensor if faulty.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $500
Moderate
• Honda Accord
• Honda Civic
• Honda CR-V
• Regular maintenance of the A/C system.
• Check and replace coolant regularly.
• Inspect wiring for wear and tear.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have your vehicle inspected by a professional if the A/C is not working properly.
• Monitor engine temperature to prevent overheating.
Check with your vehicle manufacturer for specific warranty coverage on the A/C system and sensors.
This code has been more prevalent in vehicles with electric A/C compressors, which are becoming more common in modern cars.
Moderate – While the vehicle may still be drivable, ignoring this issue could lead to further engine or A/C system damage.
Driving with an overheating engine can cause severe damage and may not be safe. Address this issue promptly.
• Engine running
• A/C system activated
The electric A/C compressor is typically located near the front of the engine bay, while the engine coolant temperature sensor is usually near the thermostat housing.
Q: Can I drive with a P1D42 code?
A: It's not recommended to drive for long periods with this code, as it may lead to engine overheating or A/C failure.
Q: How can I reset the P1D42 code?
A: You can reset the code using an OBD-II scanner, but it's important to fix the underlying issue first.
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Universal · Digital multimeter
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector 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.