P0E87: Battery Charger B Input Voltage Too High
What to do
Charging will be slower — often close to half the usual rate — while the car otherwise behaves normally. If charging has got slower, note by how much: a clean halving points here rather than at the battery or the charge point.
What this code means
On a car with two on-board chargers, the supply reaching the second charger is above its upper limit.
A second on-board charger is not a spare — it is capacity, and knowing that changes what a fault means.
Alternating-current charging is limited by the charger, not by the battery. A pack that can accept a hundred kilowatts from a rapid charger will still take all night on a domestic socket, because the on-board charger converting the mains is the bottleneck. So a manufacturer wanting faster AC charging fits a bigger charger — or two.
Which means losing charger B is a halving rather than a failure. The car still charges, at roughly half the rate it used to, with no warning light the driver would notice and nothing wrong with the charge point. The complaint that arrives is "it has got slower", months after the fault, and it is exactly the complaint that gets attributed to the battery ageing or to the charge point being tired.
The discriminator is that the rate will have halved rather than drifted. Battery ageing is gradual and proportional; losing a charger is a step change to a specific number. Ask what the car used to draw and what it draws now, because a clean halving is close to diagnostic on its own.
Rare, and usually the supply rather than the car — a generator, or an unexpected voltage through an adapter. See P0D28.
Likely causes
Start here
- Fault in the external charging equipment · easy
- Charging system overvoltage · specialist
- Faulty on-board charger · specialist
Less common
- Corroded or loose connector · specialist
- Damaged wiring harness · specialist
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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