Indoor PCB Error

What it means

This code appears on Toshiba residential split air conditioners when the fault code is read with the remote check function. It means the indoor control board has detected a fault in its own circuits that does not fall under another specific code. The unit stops or does not respond to the remote properly until the fault is fixed. The same code can mean something else on other brands, and Toshiba commercial units use different codes.

Models covered: Toshiba residential split air conditioners (RAC) that show a two-character check code through the remote check function; Toshiba commercial units use different codes.

Related codes: 110C0D04

Symptoms4

• The unit will not run, or stops after start with blinking lamps.
• Code 12 is found with the remote check function.
• Erratic response to the remote or self-restarts.
• The fault appears after a lightning storm or voltage swings.

Possible causes5

• Voltage fluctuation or a surge that damaged board components.
• Moisture or condensate reaching the board.
• Insects or dust inside the board box causing a short.
• Loose connectors on the board after earlier service.
• Board components aging and failing with heat.

How to diagnose5

1. Read the code with the remote check function: press and hold the check button, then step through the codes with the timer button until the indoor unit beeps continuously; the code shown then is the fault. Steps vary slightly by remote, so follow the owner's manual.
2. Switch off at the breaker for several minutes and restart; the fault sometimes clears if it was caused by a passing voltage swing.
3. Note whether a power cut or voltage swing came before the fault.
4. With power off, the technician inspects the board for burns, moisture or insects and checks the connectors.
5. The technician confirms the sensors and fan motor are healthy before condemning the board, since their faults can affect board readings.

How to fix5

1. Restart after switching off at the breaker if the fault was a one-off.
2. Clean and dry the board, tighten connectors and seal its box.
3. Fit a voltage protector to shield the board from fluctuations.
4. Replace the indoor control board with the correct part for the model from an authorized service center.
5. Run the unit, test all modes and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low if cleaning and connector work solve it, and rises when the indoor control board has to be replaced.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions