What it means
The HV battery pack coolant pump B reports a supply voltage circuit condition. Battery thermal management may be impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Battery coolant pump B circulates coolant through part of a hybrid or electric vehicle’s high-voltage battery thermal-management system. This code sets when the pump B supply-voltage circuit has a fault, which can prevent the pump from operating and impair battery temperature control.
Common causes
Most likely first.
- Blown fuse or interrupted supply wiring
- Loose or corroded electrical connection
- Pump electrical fault
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Save freeze-frame data and use a compatible scan tool to check pump B commands, battery temperatures, and related hybrid or EV warnings.
- Inspect the accessible pump B connector and low-voltage wiring for a loose connection, corrosion, or damage; do not disturb high-voltage components.
- Check the relevant fuse and supply path for an open circuit using the vehicle’s wiring information.
- Measure supply and ground at pump B under the commanded condition, comparing results with the manufacturer’s specification.
- If the supply circuit is sound, test pump B for an internal electrical fault using the manufacturer’s procedure.
Common fixes
- Seat and secure a loose pump B connector.
- Replace a confirmed blown fuse after checking for the cause of the failure.
- Repair corroded terminals or damaged supply wiring.
- Replace pump B if its electrical fault is confirmed.
Can I keep driving?
Avoid fast charging, heavy acceleration, and long journeys while the hybrid or EV warning is active; the battery may not be cooled correctly and the vehicle may limit power. Arrange prompt diagnosis, especially if charging is restricted or a battery-temperature warning appears.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.