ACiQ PC01 error code

What it means

PC01 means the outdoor unit saw supply voltage or DC bus voltage outside the expected range. It may be a utility/brownout issue, wiring issue, or outdoor-board fault.

Urgency

Likely causes

1. Brief power event, brownout, or unstable supply voltage
2. Loose power connection, reactor, or outdoor electrical component problem
3. Inverter/IPM protection or current-detection fault
4. Compressor winding, drive, or outdoor board fault after power checks pass

Homeowner fix

Turn the system off and note whether lights dimmed, storms occurred, or other appliances had power trouble. Reset once only after power is stable. If PC01 returns or any breaker trips, stop there.

When to call a pro

Call a licensed HVAC technician or electrician if PC01 returns, a breaker trips, or other circuits show voltage trouble. Tell them the code is outdoor voltage protection.

Repair vs replace

This is normally a repair diagnosis, not an automatic replacement signal. If a technician confirms a major board, compressor, fan motor, or refrigerant-circuit repair on older out-of-warranty equipment, compare the quote with replacement.

• ACiQ Multi-Zone Extreme Series 2-Zone 18,000 BTU R-454B 208/230V (ACIQ-18Z-HH-M3C)

  Multi-Zone Extreme Series

• ACiQ Multi-Zone Extreme Series 3-Zone 27,000 BTU R-454B 208/230V (ACIQ-27Z-HH-M4C)

  Multi-Zone Extreme Series

• ACiQ Multi-Zone Extreme Series 4-Zone 36,000 BTU R-454B 208/230V (ACIQ-36Z-HH-M5C)

  Multi-Zone Extreme Series

• ACiQ Multi-Zone Extreme Series 5-Zone 48,000 BTU R-454B 208/230V (ACIQ-48Z-HH-M6C)

  Multi-Zone Extreme Series

For your technician

Technician note: section 7.4.2.5 covers E5/PC10/PC11/PC12 voltage rise/drop detection; verify supply and DC bus before replacing boards. Page context: ACiQ maps this display to the Multi-Zone Extreme Series line; source: ACiQ Multi-Zone Service Manual and shared Midea D5CMRA Table 20 display reference; display convention: match the letter P, letter C, and one marker exactly before comparing neighboring codes.

Which systems show it

• ACiQ Multi-Zone Extreme Series R-454B systems using the shared Midea/ACiQ multi-zone platform.
• ACiQ Multi-Zone Standard Series R-454B systems where the ACiQ service manual lists the same EC/EH/EL/PC diagnostics.
• ACiQ wall-mounted, cassette, duct, console, and AHU indoor units listed in service manual section 7.2.

Sold under more than one brand

Shared with Midea. ACiQ and Midea document this code from the same manufacturer source, so PC01 means the same thing on either badge and the steps above apply.

Related troubleshooting

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

Reset note

Turn the system off and note whether lights dimmed, storms occurred, or other appliances had power trouble. Reset once only after power is stable. If PC01 returns or any breaker trips, stop there.

Manual trigger

PC01 means the outdoor unit saw supply voltage or DC bus voltage outside the expected range. It may be a utility/brownout issue, wiring issue, or outdoor-board fault.

Related codes

Source

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