P2CF5: Hybrid/EV Battery Pack Coolant Pump B Stuck/Stalled

What it means

The HV battery pack coolant pump B reports a stuck/stalled 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 moves coolant through part of a hybrid or electric vehicle’s battery thermal-management loop. This code sets when the system detects that pump B is stuck or stalled, so the expected battery-cooling flow may be unavailable.

Common causes

Most likely first.

1. Pump impeller jammed
2. Pump motor seized
3. Coolant contamination or debris

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

1. Record freeze-frame data and check battery temperatures and pump B status with a compatible scan tool.
2. Check the coolant level when safe and inspect the battery-cooling loop for leaks or visible debris, following the vehicle’s service procedure.
3. Inspect pump B’s accessible connector and low-voltage wiring for damage or a loose fit without touching high-voltage components.
4. Check for a restriction in the pump B coolant path and confirm the pump is receiving its commanded supply.
5. If supply and flow path checks are satisfactory, test pump B for mechanical seizure or impeller obstruction using the manufacturer’s procedure.

Common fixes

• Correct low coolant and repair any leak found.
• Clear a confirmed obstruction from the pump B coolant path using the vehicle’s service procedure.
• Repair a loose or damaged pump B low-voltage connection.
• Replace pump B if it remains stalled or its motor or impeller is seized.

Can I keep driving?

Avoid driving far, hard acceleration, and fast charging while the hybrid or EV warning is present; the battery may overheat without pump B circulation. Stop and seek assistance if a battery-temperature warning appears or power is sharply limited.