carrier vector 1800 error 51, 128

[average user]

Have a fridge trailer with a carrier vector 1800.
Been running fine at -20. We turn it off at night as workers sleep near vehicle and keeps them awake, then turn on first thing in the am

Turned on this morning with error 51 (alternator not charging), and error 128 (consumption amps not right)

Its just the trailer and no tractor so not sure what has caused this or what could fix it?

Any ideas before I get an engineer out?

I have a horrible feeling the compressor is out

Thanks in advance for any input, also first post so apologies if I have missed any relevant info out

[Boss302]

Highly doubt it is the compressor. Could be numerous things, but the compressor would be towards the bottom of the list.

[cadwaladr]

Alarm codes are a pointer,the vector is a electrical minefield it can lead you astray so easily downloading is the answer with this machine,a faulty sensor can send it haywire short answer call them out get it analysed ,one faulty contactor misbehaving sets loose a crazy monkey on crack!