Toshiba 21 and 1E Error Codes

What does the Toshiba 21 error code mean?

On Toshiba wall splits in the RAS series and on some older RAV units, check code 21 means a high pressure trip. In plain terms, the pressure on the high side of the refrigerant circuit climbed past a safe limit. The control board then stopped the compressor to protect it.

A trip like this is a protective action, not a failure in itself. However, the system trips for a reason, and that reason needs finding. If the cause stays in place, the unit will usually keep tripping and showing the same code.

Why does pressure rise too high in an aircon?

Pressure on the high side depends on how well the system can get rid of heat. In cooling mode, the outdoor coil releases heat into the outside air. In heating mode on a reverse cycle system, the indoor coil releases heat into the room instead.

So anything that stops the releasing coil from shedding heat can push pressure up. For example, a coil choked with dust, leaves or lint traps heat. A fan that runs slowly or not at all has the same effect, because no air moves across the coil.

Which side of the system trips the code?

The answer depends on the mode. In cooling, technicians look first at the outdoor unit, its coil and its fan. In heating, they look first at the indoor unit, because a blocked indoor filter or a slow indoor fan can raise pressure on that side.

This is why it helps to note which mode the unit was in when the code appeared. That single detail narrows the search straight away. It also tells you which filter or coil to look at during your own safe checks.

How do you read check codes on a Toshiba wall split?

Toshiba wall splits do not have a screen that spells out the fault. Instead, they flash the lights on the front of the indoor unit. Depending on the model, you may see the operation light, the timer light and sometimes a third light such as pre heat.

What do Toshiba aircon flashing lights tell you?

A slow, steady flash of the operation light after the power comes back on is normal. It is not a fault, and it usually settles once you start the unit with the remote. In contrast, fast flashing of the operation and timer lights together means the unit has stored a fault.

Many owners search for aircon light flashing or an aircon flashing green light when they first see this. The light colour varies between models, so the pattern matters more than the colour. Write down which lights flash and how quickly before you do anything else.

How do you get the two character code?

You read the stored code with the wireless remote and its CHECK function. Point the remote at the indoor unit and start the check mode. The remote then steps through the possible codes until the indoor unit beeps on the stored one.

The exact button steps vary between remote models, so follow the instructions in your manual. If a Toshiba air conditioner blinking light appears but you cannot find the code, note the pattern and leave the reading to a technician. Our main Toshiba air conditioner error codes page explains the general process and lists the other codes.

When do you need a technician for these codes?

You need a technician when the code returns after a reset and your basic checks. A repeated 21 or 1E trip means something in the system keeps pushing pressure or temperature past its limit. Running it over and over in that state places extra strain on the compressor.

Call for help sooner if you notice any of these signs.

• The outdoor fan does not spin while the compressor seems to run.
• The unit trips within minutes of every restart.
• You hear loud knocking, rattling or a harsh hum from the outdoor unit.
• You smell burning or see scorch marks near the unit.
• The breaker trips at the same time as the code appears.

What will the technician check first?

A technician will usually start with airflow, because it is the most common and simplest cause. They check both coils, both fans and the filters. Next, they connect gauges and measure the working pressures in the mode that tripped.

After that, they read the temperatures at key points around the circuit. Comparing pressures with temperatures shows whether the charge is right, whether something restricts the flow, or whether the system holds too much refrigerant. Finally, they check the sensors and the protection devices that raised the code.

Could the cause be a faulty sensor?

Yes, a sensor or switch can fail and report a fault that is not really there. Wall splits use a discharge sensor called TD, and a separate code, 19, covers a TD or TL sensor open or short circuit. A technician can measure the sensor and compare its reading with the real pipe temperature.

If the sensor reads correctly, the fault lies in the refrigerant circuit or the airflow. If it reads wrongly, replacing the sensor may solve the problem. Either way, testing beats guessing, because swapping parts at random wastes your money.

How do technicians repair these faults?

The repair follows the cause, so it can range from a simple clean to major work. A coil clean and a fan repair sit at the lighter end. Leak repairs, restriction repairs and compressor work sit at the heavier end.

What does a typical repair process look like?

1. The technician confirms the code and the conditions when it appeared.
2. They inspect airflow, coils, fans and clearance around both units.
3. Next, they measure pressures and temperatures with the system running.
4. They test the relevant sensors and protection devices.
5. Then they explain the likely cause and the repair options to you.
6. With your approval, they carry out the repair and retest the system.

Is a repeated trip bad for the compressor?

Each trip protects the compressor, so the system does its job when it stops. However, a system that keeps tripping and restarting puts the compressor under repeated stress. Over time, that stress can shorten its life, so it pays to deal with the cause early.

For a closer look at how faults get diagnosed and fixed, see our guide to Toshiba air conditioner repairs. It covers common failed parts and when repair makes more sense than replacement.

Getting help with a 21 or 1E fault

A 21 or 1E code means your Toshiba system protected itself from pressure or heat it could not handle. Simple checks on filters, clearance and power can sometimes clear the cause. If the code keeps returning, the system needs proper measurement rather than repeated resets.

We book local technicians across Victoria, New South Wales, Queensland, South Australia, Western Australia and the ACT. We are an independent service and not affiliated with Toshiba. If you would like a technician to look at your unit, you can contact us and we will arrange a visit at a time that suits you.