Carrier PC01 error code

What it means

PC01 means the outdoor unit detected voltage outside the expected range. The system may stop to protect the inverter and compressor electronics.

Urgency

Likely causes

1. Carrier Table 4 identifies PC01 as outdoor-unit voltage protection.
2. Carrier troubleshooting lists voltage too high or too low as a possible cause.

Homeowner fix

Power cycle once at the breaker if you can do that safely. If PC01 returns, the breaker trips, or lights in the home dim or flicker, stop and call for service.

When to call a pro

Call a licensed HVAC technician or electrician if PC01 returns, the breaker trips, or other lights/appliances show voltage symptoms.

Repair vs replace

Supply-voltage corrections are usually repairable. If voltage has damaged the outdoor inverter board on an older unit, compare the board quote with replacement.

• Carrier Comfort 22 9,000 BTU R-454B 115V (45MHHAQ09XC1 / 37MHRAQ09AA1)

  Comfort 22

• Carrier Comfort 22 9,000 BTU R-454B 208/230V (45MHHAQ09XC3 / 37MHRAQ09AA3)

  Comfort 22

• Carrier Comfort 22 12,000 BTU R-454B 115V (45MHHAQ12XC1 / 37MHRAQ12AA1)

  Comfort 22

• Carrier Comfort 22 12,000 BTU R-454B 208/230V (45MHHAQ12XC3 / 37MHRAQ12AA3)

  Comfort 22

For your technician

Technician note: verify incoming voltage under load, disconnect/breaker condition, grounding, DC bus, and outdoor-board power circuits. Page context: Carrier maps this display to the Comfort 22 line; source: Carrier 45MHHAQ High Wall Heat Pump Owner's Manual, Table 4 Error Codes; display convention: match the letter P, letter C, and one marker exactly before comparing neighboring codes.

Which systems show it

Comfort 22

Related troubleshooting

Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.

Related codes

Source

Next step