P0E85: Battery Charger B Voltage Sensor Circuit

What it means

The ECM detects a circuit fault on the battery charger b voltage sensor circuit. Reading cannot be used reliably for control.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Battery charger B uses a voltage sensor to report an electrical measurement to the control module during charging. P0E85 sets when the sensor circuit has an electrical fault, so the module cannot rely on that reading to control charger B.

Common causes

Most likely first.

1. Sensor failed
2. Wiring or connector fault

Symptoms

• Charge status indicator shows fault
• Charging may not start or interrupts
• Slower-than-expected charge rate

How to diagnose it

1. Read freeze-frame data and charging-related live data to determine whether the fault occurs before charging or while charger B is operating.
2. Inspect the charger B voltage sensor connector and accessible wiring for looseness, corrosion, or damage.
3. Check the sensor circuit for an open, short, or poor terminal contact using vehicle wiring information.
4. Compare the voltage sensor output with the actual measured circuit voltage using the manufacturer’s diagnostic procedure.
5. If wiring and connections pass inspection, test the voltage sensor and charger B input as specified by the manufacturer.

Common fixes

• Reconnect or clean the voltage sensor connector.
• Repair damaged wiring or loose terminals in the charger B voltage sensor circuit.
• Replace the voltage sensor if its output fails the specified test.
• Repair charger B if the sensor circuit is sound but the charging fault remains.

Can I keep driving?

Charging may be limited or may stop, so do not rely on a planned charge completing until the warning is resolved. The vehicle may remain drivable on its available battery charge, but avoid letting the battery run low.