Bosch Fridge Freezer KGS3222 Failure

Bosch KGS3222 twin compressor "duo system " fridge freezer (2002?? Vintage) has failed. Sometimes either fridge or freezer will work or both fail. I have been advised that the sequence in which the temperature indicator lights flash probably defines a fault code but I am unable to find any information on this. The sequence is two longer flashes of the two green temperature lights followed by a shorter flash at which point the red freezer alarm light also flashes off briefly.
Can anyone please help? Thanks.