I have two flashes on the timer light of my indoor unit of Fujitsu Inverter ASU9RLS

found this....

https://www.absoluteservices.com.sg/articles/how-to-solve-panasonic-aircon-light-blinking-problem.html

hope it helps.

Best to you.

Red 4 Flashes Green 4 Flashes Power Failure

Off 3 Flashes Reverse Comms Fail In Use

I have one of these units and it has had its fair share of troubles, but great when it is working. My latest issue is the the flap on the indoor unit doesn't open!

This generally works for me. Pull out the isolator outside on the wall or disconnect at the breaker. Leave for a couple of hours. Reconnect and wait 15 minutes. If you are connecting via the isolator you will hear relays clicking and solenoids rattling as the unit goes through a Self Test procedure, then try normal operation.

Blink Codes and Troubleshooting.

https://www.orionair.co.uk/PDF/fujitsu-trouble-shooting.pdf

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Well manual says if light flashes there has been a loss of power. Page 8 provides info on set timer. Hope this manual will help.
Fujitsu ASGA30JCC-B, ASGA18JCC-B, ASGA24JCC-B Operating instructions ' Manualzz

Serial signal error meaning the outdoor is not talking to the indoor unit. It usually means a faulty inverter / controller board which will have to be replaced. Get a tech to confirm.

Serial communication error. This means that the indoor unit is not communicating with the outdoor unit usually because the outdoor unit is faulty. You can check the indoor unit by switching it to 'fan' mode and seeing if all functions work normally (fan speed, louvers move as directed). If it responds normally, then it's probably ok so you can turn your attention to the outdoor unit. A common problem with the outdoor controllers is that they are susceptible to bugs, geckos, etc. shorting them out which will mean replacement of the board.

A continuous blinking timer light is a "model error" meaning the indoor and outdoor unit is mismatched. If the timer light flashes a number of times, pauses, then repeats, count the number of flashes and then you can work out the error code.

This is a "PFC circuit abnormal" in the outdoor unit meaning that the outdoor controller board is faulty. Try turning the machine off at the isolator switch for 10 mins, then back on to see if the error resets. If not you will need a new controller PCB.

fujitsu is a good brand.
try one of these two things:

Turn the unit off then on again. After that press test button on remote control (rear side) and look how many times now operation and timer LED flashes. Note that. Then press MANUAL/AUTO button on indoor unit until you hear 3 beeps from buzzer. That will erase error memory.
Switch off and than on unit and see if indication repeat or it is gone. If it is gone, keep using your unit.
If it is repeated post your notes here.

OR+++++++++++++++++++++FOR OTHER MODELS

5 x Operation flash and a constant Timer flash indicates an outdoor unit control error. With this code flashing on the indoor unit, you need to point the remote at the unit and push the test run button. The flash pattern will change to a continuously flashing Operation light and a number of flashes of the timer light which gives more detail on what the error is.

To get the unit to try to restart you need to push and hold the manual/auto button on the indoor unit for a few seconds then reset the mains power supply but leave it off for a minute or so for the unit to power down completely. If you are going to try this make sure you make a note of any error codes first if you have to get someone out to look at it, it will help them a lot.

Please mark this answer helpful.

The indoor unit has the problem and it's the air thermistor. You need to replace it.

If the operation button is flashing 8 times, the timer light should also flash 4 times in each sequence. This indicates a failure of the PFC circuit in the outdoor unit which basically means a faulty outdoor board and will have to be replaced.
If the operation light is flashing 8 times by itself, the indoor controller board may have a fault. You can normally test this by putting the mode on the remote to 'Fan' and checking that the controls otherwise work normally - louvers work as directed and fan speed changes correctly when selected on the remote.
Most likely the fault lies in the outdoor board but you should contact a tech to diagnose correctly.