Cause
Excessive electrical load
More electrical demand than the charging system can meet, so system voltage falls. It is a condition rather than a component fault, and it appears when demand and supply are momentarily mismatched — a cold night with lights, heated screens, seats and a blower all running while the engine idles.
A modern vehicle manages this deliberately, shedding non-essential loads and raising idle to increase alternator output. The codes are that management reporting it reached its limits, so they describe a heavily loaded system rather than a broken one.
The question is whether the load is legitimate. Added equipment — a large amplifier, auxiliary lighting, a winch — can exceed what the alternator was sized for, and the vehicle then undercharges in normal use. Measure charging voltage with everything switched on at idle: a voltage that sags below the battery's resting value means the system is discharging while running, which is the definitive finding. A tired battery makes it worse, since it has less reserve to cover the gap.
Typically a moderate job.
Codes this can cause (2)
Codes where this is a likely explanation first, rather than merely a possible one.
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