Fujitsu fault

[Gary S]

Hi all.
Would appreciate some help on this one.
Have a fujitsu split with a cassette and outdoor double fan unit model: AOY54LJBYL 230 volt R410a . got a EE fault on wall mounted controller. pressed up and down buttons and got 0A which refers to outdoor ambient sensor fault.
ordered and replaced this sensor and restarted unit. both outdoor fans ran and a minute later the compressor appeared to try start.( in heating mode)
then unit went off and wall mounted controller read the dreaded EE. pressed up down and read 0A again. reset a few times and same thing. the outdoor pcb led is flashing 4 times quickly which refers to outdoor temp sensor fault (open)
Anyone have this before??
starting to think maybe the outdoor pcb is dodgy but not sure.
All help gratefully received.

thanks
Gary

[Tayters]

Hi Gary,

The code means the outdoor PCB has detected the outdoor air temp probe (plugged into CN23) has read open or short circuit (0V or 5V siganl coming back from the probe to the PCB.

I'd confirm the correct resistance of the probe when unplugged - 27k ohm at 5*C, 20k ohm at 20*C.
Check if there is 5V DC across the probe terminals when probe is unplugged and somewhere between 1 and 4V when plugged in depending on probe temp, this voltage should also change if you heat / cool the probe.
If the probe measures fine then all that's left is the PCB or the connectors on the PCB - dry joint perhaps.

If the fan motors are the metal body type then swap them for the superseded white plastic body type before they take the PCB out. Those fans are a waiting time bomb!

Cheers,
Andy.

Might be worth trying topower the unit off for a good couple of minutes just incase the unit has still stored the fault as a current one. Unlikely I know but worth a shout old chap.