06/06/2026 8:38 am
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2012 Prius P0A80: one battery block drops 1.2 V only under acceleration
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A 2012 Prius sets P0A80 during a long uphill drive. At rest, all battery blocks are within 0.18 V. Under firm acceleration, block 11 falls about 1.2 V below the highest block and its calculated resistance is consistently higher. Cooling-fan intake is clean and battery temperatures agree.
Is the loaded voltage spread sufficient to condemn the pack, and what should remain outside a general repair bay?
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23/08/2026 11:08 am
The repeatable loaded deviation and higher resistance are meaningful, but verify scan-tool accuracy, bus-bar sense connections and temperature conditions before deciding. Compare the same block during charge and discharge and inspect only through the manufacturer’s high-voltage procedure. A loose sense connection can create an apparent block fault.
Do not open the battery case or probe exposed high-voltage points without the required qualification, PPE, isolation and zero-voltage verification. If external sensing checks are intact and block 11 repeatedly diverges under load, refer the pack for approved repair or replacement rather than mixing unmatched modules.
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24/08/2026 7:44 am
A hybrid-qualified technician confirmed the sense circuit was secure and block 11 diverged in both directions. The complete approved battery assembly was replaced. Block spread stayed below 0.25 V on the same hill and P0A80 did not return.