Aftermarket alarm help

[8000ft tuning]

I've been trying to tune a 2017 truck that unknown to me or the owner had an after market alarm since tuning his truck for bolt-ons he has told me it dies at random he is getting check engine lights that report no code stabitrac warnings and erros as far as stuff I have done in the tune is change ignition timing fueling and calibrated the spedo for bigger tires I haven't had this ever happen before and I put the stock as found back in its doing the same thing does anyone have any ideas.

[HaCKoWeLL]

what brand? I do these for a living