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Code P1D20

Symptoms

• A/C system not cooling properly

• Warning light on the dashboard

• Possible overheating of the A/C compressor

Common Causes

• Faulty internal temperature sensor 'B'

• Overheating of the A/C compressor

• Electrical issues within the control module

Glossary

A/C: Air Conditioning

Compressor: A component that compresses and circulates refrigerant in the A/C system

Related Codes

• P1D21

• P1D22

Laymans terms

The car's air conditioning system has a sensor that checks how hot it is inside the part that cools the air. This sensor is saying it's too hot.

Explanation

The internal temperature sensor 'B' within the electric A/C compressor control module is detecting a temperature that is higher than the expected range.

Technical description

The P1D20 code indicates that the Electric A/C Compressor Control Module has detected an internal temperature sensor 'B' reading that is higher than the normal operating range. This could be due to a malfunctioning sensor, an overheating issue, or a fault within the control module itself.

Diagnosis steps

• Check for any stored codes and freeze frame data.

• Inspect the A/C compressor for signs of overheating.

• Test the internal temperature sensor 'B' for proper operation.

Repair procedures

• Replace the faulty internal temperature sensor 'B'.

• Repair or replace the A/C compressor if overheating is detected.

• Inspect and repair any electrical issues in the control module.

Tools required

• OBD-II scanner

• Multimeter

• Thermal camera or infrared thermometer

Estimated repair cost

$200 - $800

Difficulty level

Moderate

Commonly affected vehicles

• Honda Accord

• Honda Civic

• Acura MDX

Preventive measures

• Regularly service the A/C system.

• Ensure proper airflow to the A/C compressor.

• Check for any leaks or blockages in the system.

Error code type

Sensor Issue

User experience recommendations

• Do not ignore the warning light; get it checked soon.

• Avoid using the A/C until the issue is resolved to prevent further damage.

Warranty information

Check if the vehicle's warranty covers A/C system components.

Historical data

This code has been reported in vehicles with electric A/C compressors, particularly in models with advanced climate control systems.

Urgency level

Moderate – Addressing this issue soon can prevent further damage to the A/C system.

Legal and safety notice

Driving with a malfunctioning A/C system can lead to discomfort and potential overheating issues.

Testing conditions

• Vehicle must be running with the A/C system on.

• Ambient temperature should be within normal operating range.

Component location

The electric A/C compressor is typically located in the engine bay, connected to the engine via belts and hoses.

FAQs

Q: What does the P1D20 code mean?
A: It means the internal temperature sensor 'B' in the A/C compressor is reading too high.

Q: Can I drive with the P1D20 code?
A: It's best to get it checked soon to avoid further damage to the A/C system.

Last updated: Jun 9, 2026 • Source: internal database
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