P0D85: Battery Charging Output Voltage Too High
What to do
Do not keep trying to charge. The car has stopped for a reason that can permanently damage the battery and, in the worst case, start a fire. This needs a shop equipped for high-voltage work before the car is charged again — including from a home charger.
What this code means
The voltage being delivered to the traction battery during charging is above its safe upper limit.
Of every number this car measures, this is the one with the least margin for error, and the reason is chemistry rather than engineering. A lithium cell has a maximum voltage above which the electrolyte begins to break down and lithium plates out onto the anode as metal. That damage is cumulative and permanent — the cell does not recover when the voltage comes back down, it simply holds a little less charge than it did, for ever.
Push far enough and the failure stops being gradual. Plated lithium grows in structures that can eventually bridge a cell internally, and an internally shorted lithium cell is the mechanism behind battery fires that begin hours after charging finished.
So the car does not treat this as a performance issue. It stops charging, and it should: the protection is layered deliberately, with the charger's own measurement at P0D4C and the battery management system's separate one, precisely so that no single sensor failure can allow it.
A car storing this has had a real over-voltage event or has lost confidence in the measurements that prevent one. Neither is something to clear and retry.
Likely causes
Start here
- Faulty on-board charger · specialist
- Faulty battery pack sensor module · specialist
Less common
- Corroded or loose connector · specialist
- Charging system overvoltage · specialist
- Fault in the external charging equipment · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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- The car — make, model, year and engine. The same fault behaves differently on each.
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