The PC00 error code in air conditioners is often associated with a failure in the IPM electronic module or the overcurrent protection of the IGBT transistor. Below are the recommended steps to diagnose and resolve this issue:
Diagnostic Steps
1. Disconnect the Unit:
- Turn off the air conditioner and disconnect it from the power supply for a few minutes.
2. Reconnect and Observe:
- Reconnect the unit to the power supply and check if the error disappears.
3. Check the Power Supply Voltage:
- Use a multimeter to verify that the electrical supply voltage is within normal operating parameters.
4. Inspect for Abnormal Current Consumption:
- High current consumption may indicate issues such as faulty electrical connections or poor contacts. Inspect all cables and connections for signs of damage or looseness.
- Problems with the outdoor unit fan or dirt in the heat exchanger may cause system overpressure and excessive current consumption. Inspect the fan and clean the heat exchanger if necessary.
5. Check the Compressor’s Electrical Integrity:
- Disconnect the compressor and measure the electrical resistance between its connector pins using a multimeter set to the ohms scale. All resistance values should be equal and not display infinity.
- Measure the resistance between each pin and the compressor casing using the megaohms scale. The value should be infinite, indicating no ground leakage.
6. Examine the Outdoor Unit’s Electronic Controller:
- Observe the indicator LEDs on the electronic board:
- If the LEDs are active: Inspect the IPM circuit, which distributes the DC voltage.
- If the LEDs are inactive: Focus on inspecting the PFC circuit (voltage generation).
7. Verify the PFC Circuit:
- Check for the presence of DC voltage on the board, especially at the output of the PFC circuit’s rectifier bridge:
- For 110V AC input: Expect approximately 150V DC output.
- For 220V AC input: Expect approximately 300V DC output.
- Without powering the board, verify electrical continuity between the input and output of the PFC reactor or coil.
8. Inspect PFC Circuit Components:
- Check the resistors, diodes, capacitors, and continuity of the circuit traces.
- Inspect the condition of the IGBT transistor in the PFC circuit.
Verifying the IPM Electronic Module
1. Disconnect the Unit:
- Ensure the capacitors are discharged before proceeding. Use a multimeter set to the DC voltage scale to confirm capacitor discharge.
2. Locate the IPM Circuit:
- The IPM module is typically covered by heat dissipation fins and connected to the compressor via three independent tracks.
3. Identify Power Supply Tracks:
- Positive: Follow the track from the high-voltage capacitors to the IPM module.
- Negative: Trace the negative track in the same manner.
4. Identify Output Points (U, V, W):
- Trace the paths from the compressor connectors to the IPM module.
5. Perform IPM Module Integrity Tests:
- Set the multimeter to the diode test mode.
- Check the internal diodes of the module:
- Place the black probe on the positive input and measure U, V, W with the red probe.
- Repeat with the red probe on the negative input and the black probe on U, V, W.
- Voltage activation values should be consistent and approximately 0.45V.
