Toshiba air conditioning service

Toshiba F Series Error Codes

What the Toshiba F series codes mean, what you can check and when to book a technician.

When a Toshiba ducted, cassette or VRF system shows a code starting with F, it is telling you about a sensor or a memory chip. Toshiba F error codes cover the temperature sensors inside the indoor and outdoor units, plus the memory on each circuit board. They appear on the wired wall controller as the letter F followed by two digits.

This page walks through each F code in the range from F01 to F31, what it generally points to and why the system reacts the way it does. You will also find the safe checks you can try and the point where a technician should take over. Meanings can vary by series and generation, so always confirm the code against the manual or service label for your exact model.

What are Toshiba F error codes?

Toshiba groups its wired controller codes by letter. The E series covers communication, the H series covers the compressor, the L series covers setup, and the P series covers protection. The F series sits apart because it deals with the parts that measure and remember things.

Most F codes relate to a thermistor. A thermistor is a small sensor whose electrical resistance changes as temperature changes. The circuit board reads that resistance and turns it into a temperature, so the system knows how hot or cold each part of the refrigerant circuit is running.

If a code appears straight after installation or a board change, also check the L series codes, which cover setup and addressing.

Two F codes are different. F29 and F31 point to the memory on the indoor and outdoor boards.

Which Toshiba systems show F codes?

F codes belong to the RAV and SMMS families. That means ducted units, ceiling cassettes, under ceiling units and VRF systems with a wired controller on the wall. In Australia, the current ducted range is the RAV series, and AHI Carrier distributes Toshiba equipment here.

Wall split systems work differently. Models such as Seiya, Seiya Classic, Shorai Edge and Haori belong to the RAS series. Instead of an F code on a screen, they flash the lights on the indoor unit. You then read a two character check code using the CHECK function on the wireless remote.

Why does a sensor fault stop the system?

The boards rely on sensor readings to make dozens of decisions. For example, they use coil temperatures to judge when to defrost, how fast to run the fan and how hard to drive the compressor. If a reading becomes impossible, the board has nothing sensible to work with.

So rather than run blind, the system stores a code and either stops or limits itself. This is a protective step, not a sign that the whole unit has failed. In many cases the fault sits in a single sensor, a plug or a short length of wire.

What does each Toshiba F series code usually mean?

The list below follows the meanings in published Toshiba fault references for RAV and SMMS equipment. Treat it as a guide only. Your model may use slightly different wording or assign a code differently, so check the manual or the label inside the unit.

Indoor sensor codes F01, F02 and F10

These three codes point to sensors inside the indoor unit.

F01 points to the indoor heat exchanger sensor called TCJ.
F02 points to the indoor heat exchanger sensor called TC2, or TC on some units.
F10 points to the indoor return air sensor called TA.

The heat exchanger sensors sit on the pipework of the indoor coil. They tell the board how cold the coil runs in cooling and how warm it runs in heating. As a result, the board can protect the coil from freezing and manage the fan speed.

The TA sensor reads the air coming back into the unit. On a ducted system, this is the return air. The board compares that reading with your set temperature, then decides whether to keep working or ease off.

Outdoor sensor codes F04, F06, F07, F08 and F12

These codes point to sensors on the outdoor unit.

F04 points to the outdoor discharge temperature sensor called TD.
F06 points to the outdoor heat exchanger sensor called TE.
F07 points to the outdoor TL sensor.
F08 points to the outdoor air temperature sensor called TO.
F12 points to the suction sensor called TS.

The TD sensor watches the hot gas leaving the compressor. That reading helps the board stop the compressor from overheating. Without it, the system cannot protect its most expensive part, so it shuts down.

The TE sensor reads the outdoor coil. In heat mode, the outdoor coil runs cold and can frost over, so the board uses this reading as part of its defrost decision. Meanwhile, the TO sensor measures the outside air, which helps the system adjust to the weather.

The TS sensor sits on the suction side, where refrigerant returns to the compressor. The TL sensor reads another point on the outdoor pipework. Together, these readings give the board a picture of how the refrigerant circuit is behaving.

Heat sink code F13

F13 points to the heat sink sensor called TH. The heat sink is a metal plate that draws heat away from the power electronics on the outdoor inverter board. If the TH reading becomes impossible, the board cannot judge whether those electronics are safe. It therefore stops the system rather than risk damage.

Memory codes F29 and F31

These two codes concern circuit board memory rather than sensors.

F29 points to an indoor board memory fault.
F31 points to an outdoor board memory fault.

The memory stores information such as capacity settings and operating data. Sometimes a power interruption triggers a one off error, and the code clears after a proper restart. However, a code that keeps returning usually points to a board problem that needs testing.

Why do sensor faults happen?

A sensor code does not always mean the sensor itself has died. The board only knows that the reading looks wrong. Several different problems can produce that result.

Common causes behind an F code

The thermistor has failed internally, which is common as sensors age.
A plug on the circuit board has worked loose or corroded.
The sensor wire has broken, often where it bends or passes near a sharp edge.
Pests have chewed the wiring, especially in roof spaces and outdoor units.
Moisture has reached a connection and caused corrosion.
The sensor has slipped off its pipe, so it reads the wrong spot.
The board input that reads the sensor has failed.

Because so many causes look the same to the board, guessing at a part rarely works. Instead, a technician tests the sensor and the circuit before deciding what to replace.

Does weather or season play a part?

Sometimes it does. Outdoor sensors live in heat, cold, rain and dust all year. That exposure can slowly break down insulation and connectors, so outdoor codes such as F04, F06 and F08 may appear after a storm or a very hot spell.

Indoor sensors face different conditions. Condensation in a ceiling cassette or a ducted unit in a hot roof space can affect connections over time. In addition, roof spaces attract rodents, and chewed sensor leads are a well known cause of indoor faults.

How do you read an F code on the wired controller?

On most Toshiba wired controllers, the code appears on the screen when the system stops. You may see the letter F and two digits, sometimes with a unit number on multi unit installations. Write the code down exactly as it appears before you do anything else.

Many wired controllers also keep a fault history. On these models, holding the CHECK button brings up the stored codes. The exact steps differ between controllers, so follow the instructions in your controller manual rather than pressing buttons at random.

What if your unit flashes lights instead?

If you have a wall split with no wired controller, you will not see an F code. Instead, you get an aircon light flashing on the indoor unit. Many people search for an aircon flashing green light, Toshiba aircon flashing lights or a Toshiba air conditioner blinking light when this happens.

On RAS wall splits, a slow flash of the operation light after power returns is normal and is not a fault. Fast flashing of the operation and timer lights together points to a stored fault. You then use the CHECK function on the remote to find the two character code. Our guide to Toshiba air conditioner error codes explains that process in more detail.

How do wall split codes relate to F codes?

The two systems describe some of the same sensors in different ways. For example, a wall split may report an outdoor coil sensor problem as code 18, while a wired controller might show F06 for a similar sensor. The Toshiba 18 and 19 error codes page covers those outdoor sensor codes for wall splits.

That said, do not assume a direct match between the two lists. Meanings can vary by series, and the manual for your model remains the final word.

What can you safely check yourself?

There are a few simple steps you can take before calling anyone. None of them involve opening covers or touching wiring. If a step needs a tool, it is not an owner task.

Note the full code, the unit number if shown and the time it appeared.
Turn the system off at the controller.
Switch off the isolator or the circuit breaker for the system.
Wait a few minutes so the boards fully power down.
Restore power and start the system again.
Watch whether the same code returns, and how quickly.

While the power is off, it is also worth checking the basics. Make sure the filters are clean and the outdoor unit has clear space around it. Look for obvious damage such as a cable that pests have chewed near the outdoor unit, but do not touch it.

What does it mean if the code clears?

If the code clears and stays away, the fault may have been a one off glitch. For example, a brief power interruption can confuse a board. Keep an eye on the system over the next few days.

However, a code that comes back points to a real fault. Sensor problems often start as an occasional error and then become constant. So if you see the same F code twice, it is time to book a check.

What should you avoid doing?

Do not remove panels, unplug sensors or try to swap parts. The boards carry mains voltage, and outdoor inverter boards can hold a charge after you turn the power off. In addition, any work on the refrigerant circuit requires a technician with an ARC refrigerant handling licence.

What does a technician do about an F code?

A technician starts with the code and the history. They confirm the meaning against the service data for your exact model, because that step prevents a wrong diagnosis. Then they check the sensor and its circuit in a logical order.

How is a faulty sensor diagnosed?

First, the technician isolates the power and locates the sensor named by the code. Next, they inspect the lead and the plug for damage, corrosion or a loose fit. Finally, they measure the sensor resistance and compare it with the expected value for the current temperature.

If the sensor reads correctly, the problem may lie in the wiring or the board. The technician then checks the input on the board itself. Replacing a good sensor will not fix a board fault.

How are memory faults handled?

F29 and F31 need a different approach. The technician first rules out power supply problems and loose connections. If the code persists, the board memory may need attention or the board may need replacing, depending on the model.

On some systems, a new board needs its settings entered before the unit will run. That is skilled work, and it is one reason memory codes are not a DIY job. Our Toshiba air conditioner repairs page explains the wider repair process.

Why do ducted systems need extra care?

Ducted units often sit in tight roof spaces, so reaching a sensor can take time. The technician may also check the return air path and the filter, since poor airflow can confuse readings. Regular ducted air conditioner servicing gives the technician a chance to spot worn sensor leads before they fail.

Can an F code damage your Toshiba aircon?

The code itself does not cause damage. In fact, the code exists to prevent damage by stopping the system before it runs without accurate information. That said, ignoring a repeated F code is not a good idea.

If you keep restarting the system, it may run in a way that stresses the compressor or the coil. For example, without a working discharge sensor, the board cannot judge whether the compressor is running too hot. A prompt check is usually the cheaper and safer path.

Is a sensor fault an expensive repair?

It depends on the cause, the model and how easy the part is to reach. A loose plug can be a quick fix, while a board replacement is a bigger job. A technician should explain what they found and give you a quote before starting any work.

Frequently asked questions

Do Toshiba F error codes mean the same on every model?

No. The meanings on this page come from published Toshiba references for RAV and SMMS equipment. However, codes can vary by series and generation, so confirm the meaning against your manual or service label.

Can I clear an F code by turning the power off?

Sometimes. Switching off at the isolator, waiting a few minutes and restoring power can clear a one off glitch. If the code returns, the fault is real and needs testing.

Why does my Toshiba air conditioner show F codes but my friend’s flashes lights?

You likely have different system types. Ducted, cassette and VRF units show codes on a wired controller, while wall splits flash their indoor lights. Each system uses its own code list.

Is it safe to keep using the system with an F code?

Usually the system stops itself, so you cannot use it normally anyway. Avoid forcing it to run with repeated restarts. Instead, book a check so a technician can find the cause.

Does an F code mean my unit is low on gas?

Not directly. F codes point to sensors and memory, not to refrigerant levels. A sensor fault can affect how the system behaves, but low gas has its own signs and codes.

Can a sensor be replaced without replacing the board?

Often yes. Many sensors connect to the board with a plug, so a technician can swap the sensor alone. Still, they should test the board input first to make sure the board is not the real problem.

Why did my F code appear after a storm?

Storms can bring power surges, moisture and debris. Any of these can affect outdoor sensors, connections or boards. Try a proper restart first, then book a check if the code returns.

What information should I have ready before booking?

Note the exact code, the unit number if shown and when it appeared. It also helps to know your model number from the label on the indoor or outdoor unit. That way the technician can check the service data before the visit.

Getting your F code sorted

Toshiba F error codes look technical, yet they follow a simple idea. Something that measures or remembers has stopped making sense to the board, so the system protects itself. The fix depends on whether the sensor, the wiring or the board is at fault.

Start with a safe restart and a few basic checks, then note the code if it returns. When it does, get in touch with us and we can arrange a local technician to test the system and explain the options.

Talk to us about your Toshiba system

Tell us the model, the fault and your suburb, and we will book a local technician.

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