first service

hi is any one aware of any mayor faults coming to light with there c-hr over the last 8 months mine had one off loss of power and stopped but after turning off and on again it was all good . the morning of my service it did it again but the engine light came on and stayed on , this is now two weeks later and its still in garage under investigation as they are not sure as to fault , on asking about it seems as there is 3 possibly 4 c-hrs that they have kept hold ov. and as of yet i only know its a possible wiring loom issue with mine and a parts on back order with no time frame to speak ov .i am in a rental a fiat 500x but its nothing like my loved c-hr . living in shetland i believe, . theres only a handfull of c-hrs here so to see 4 in with unknown faults its a worry . theres been a mention of carbon build up as an other possible cause . does any one have any info or same trouble
cheers one sad unhappy c-hr owner ,