Fujitsu split system fault code

[Bearman]

One for the leccies. Hopefully someone can tell me what this fault code means. I have a Fujitsu RC split system in a bedroom that is not cooling. Model AOTR12LCC. When you start it up it functions normally for a few minutes then the outdoor unit shuts down and an error code shows up on the indoor unit. The error code is : Red operation light OFF. Green timer light flashes 3 times. From what I can find out by checking online for error codes it says "Serial signal (reverse) error in operation" What exactly does that mean to a novice like me. I was thinking it might be another "gecko" fault as we get a few of them up here on the circuit boards. Can't get a leccie to look at it for some time - any ideas?
I have a good spare outdoor unit in the shed that I can pinch parts from if I knew what it was.

[87County]

Watching with interest Brian to see what the experts say. I just had a few of these RC type (Daikin) a/cs installed and I noted that there is a 4th "signal" wire in the flex between the units to enable communication for obvious reasons.

FWIW I came across this: http://www.orionair.co.uk/PDF/fujitsu-trouble-shooting.pdf

Hopefully I may learn something

Summer is coming ...

[Bearman]

Well, seeing as I didn't get any replies I went ahead and changed the circuit board out for a good one I had on another unit and "bingo" it is working perfectly. It would appear that the code is for "stuffed PCB" Hahaha!!

[scarry]

Well often if the PCB is stuffed it can’t give you the correct code anyway.

You did well.

Oh,and by the way you need a fully qualified AC mechanic,not a “leccie” to look at it.

Sorry we don’t do enough of those domestic Fujitsu units to know the codes off the top of my head.

Apart from Daikin, as the bigger units have same/similar codes to the smaller units,and we do a lot of them.

[ezyrama]

Also, after using a Fridgie and not a sparkie, put some Vicks vapourub around the PCB on the metal surface, Gecko's cant stand the stuff and it lasts for years. Its a good thing to use around the alarm sensors in the office too. stops errant alarm calls at 3am