DTC P1397:00 [MZI-3.7]: Notes

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION & POSSIBLE CAUSE

DTC P1397:00	System voltage out of self-test range
DETECTION CONDITION	This DTC indicates that the 12-volt system voltage is too high or too low during the KOEO or KOER self-test. It sets if the system voltage falls below or exceeds the calibrated threshold at any time during the KOEO or KOER self-test
POSSIBLE CAUSE	Battery or charging system concern