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 mismatch between the air conditioning system's refrigerant pressure and the outside temperature. It's like when you expect a cold drink to be icy, but it's just lukewarm.
The vehicle's control module monitors the refrigerant pressure and ambient temperature to ensure they correlate correctly. If the readings do not match expected values, this code is triggered.
The P1D39 code is set when the Powertrain Control Module (PCM) detects that the refrigerant pressure sensor and the ambient temperature sensor readings do not align with the expected correlation. This discrepancy may indicate a sensor fault or an actual issue with the A/C system.
• A/C not cooling effectively
• Check engine light on
• Unusual noises from the A/C system
• Faulty refrigerant pressure sensor
• Faulty ambient temperature sensor
• Refrigerant leak or low refrigerant level
Refrigerant: A substance used in a heat cycle to transfer heat.
PCM: Powertrain Control Module, the vehicle's central computer that controls engine and transmission functions.
• Verify the code with an OBD-II scanner.
• Check refrigerant pressure and compare with ambient temperature.
• Inspect sensors and wiring for damage or disconnection.
• Replace faulty refrigerant pressure sensor.
• Replace faulty ambient temperature sensor.
• Repair refrigerant leaks and recharge the system.
• OBD-II scanner
• Refrigerant pressure gauge
• Multimeter
$150 - $400
Moderate
• Honda Civic
• Toyota Camry
• Ford F-150
• Regularly inspect A/C system for leaks.
• Ensure sensors are functioning correctly.
• Perform routine A/C maintenance.
Sensor Issue
• Have your A/C system checked regularly.
• Address any unusual A/C performance issues promptly.
Check with your vehicle manufacturer for warranty coverage on A/C components.
This code has become more common with the increased use of complex A/C systems in modern vehicles.
Moderate – While it may not immediately affect drivability, it can lead to discomfort and further A/C system damage if not addressed.
Ignoring A/C issues can lead to discomfort and potential safety hazards due to fogged windows.
• Vehicle must be in a stable environment with known ambient temperature.
• A/C system should be operational for testing.
The refrigerant pressure sensor is typically located on the A/C line or near the compressor, while the ambient temperature sensor is usually near the front grille.
Q: Can I drive with a P1D39 code?
A: Yes, but your A/C might not work properly, which can be uncomfortable and potentially unsafe if windows fog up.
Q: How do I know if my refrigerant is low?
A: If your A/C isn't cooling effectively or you hear hissing noises, it might indicate low refrigerant.
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