The P4 error code in air conditioning systems is generally associated with issues in the operation of the inverter compressor or its control module, known as the IPM (Intelligent Power Module). However, in some cases, it may also indicate excessive pressure in the compressor discharge. Below is a detailed guide to diagnosing and resolving this error.
Common Causes of the P4 Error and Solutions
1. Issues with the Inverter Compressor or the IPM Module
Follow these steps to diagnose and resolve the issue:
- Restart the system:
- Disconnect the air conditioner for several minutes and turn it back on to check if the error persists.
- Check the voltage supply:
- Ensure the equipment receives adequate and stable supply voltage.
- Inspect the condenser and fan:
- Make sure the condenser of the outdoor unit is completely clean.
- Verify that the fan is functioning correctly and that its blades spin freely.
- Inspect the power cables:
- Check the cables that supply power to the inverter compressor, ensuring they are firmly connected.
- If the control board is faulty, the LEDs may blink rapidly as a warning signal.
- Evaluate the compressor windings:
- Use a multimeter to measure the resistance of the compressor windings, ensuring the power is disconnected.
- If the resistances are not nearly identical, the compressor should be replaced.
- Inspect the external electronic control board:
- Visually inspect the tracks of the control board, as well as the capacitors, to identify issues such as corrosion or short circuits.
- Use a multimeter to measure the resistances near the IPM module. Replace any resistance with abnormal values with a new one of the same specifications.
Brands associated with this type of issue:
Carrier, Lenox, Lloyd, Westinghouse, Midea, Hyundai, Mirage, Dking, Itachi, Mundoclima, and BGH.
2. Excessive Pressure in the Compressor Discharge
If the P4 error is related to excessive pressure in the compressor discharge, follow these steps:
- Clean the condenser:
- Ensure the condenser of the outdoor unit is thoroughly cleaned to improve ventilation and heat exchange.
- Check working pressures:
- If the system has been recently recharged with refrigerant, verify the pressures to ensure they are correct.
- Inspect the condenser fan:
- Check the condition of the condenser fan and confirm it is functioning properly.
- Test the temperature sensor:
- Check the condition of the sensor responsible for measuring discharge temperature and sending the signal to the control module.
- Use a multimeter to measure the sensor’s resistance, ensuring the value is neither zero nor infinite.
- While the sensor is connected, measure its voltage supply, which should be 2.5 V during normal operation.
Brands associated with this type of issue:
TCL, Toshiba, Trane, York, and Pioneer.
