Engine Management Light

[Invincible2008]

Morning Everyone, new to here and after some help.
I have a 2008 HiLux 3.0 D4D, I had a Battery light come on the other week and then the engine management light. Around the same time I noticed the horn was being temperamental. Tested the Battery and it was shot so replaced, but engine management light wouldn't go out.... Tested the Alternator and that had gone too, replaced and all well for around 24hrs. Then I used the horn, which again was temperamental and when I parked up the engine management light was back on. Everything else worked suggesting no relay issues and the horn was working suggesting no fuse issue, I'm pretty sure its the clock spring as now not working at all. 
However the engine light would go out and then come back on a day later, plugged in the software and it came up with an issue with the alternator regulator... Cleared the fault and all seemed well, but then it came on again... Same fault. Charging absolutely fine, but still the same fault. Local supplier very good and swapped out the alternator which was fitted yesterday and now light all the time reading same error.... P06022

Sorry for the long winded question, but struggling to understand why the fault keeps coming up.... 
Any help greatly appreciated...

[FROSTYBALLS]

Welcome to Toyota Owners Club.

Moved to the Hilux forum.