P2E49: Hybrid/EV Electronics Coolant Pump B Stuck/Stalled

What it means

Hybrid/EV electronics coolant pump B reports a stuck/stalled condition. Power electronics cooling on this branch is impaired.

At a glance

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

How it works

Pump B circulates coolant through one of the power-electronics cooling branches in a hybrid or EV. This code means the module detects that pump B is stuck or stalled, so the branch may not be circulating coolant.

Common causes

Most likely first.

1. Pump motor or driver fault
2. Air or coolant level issue

Symptoms

• Check-engine or hybrid-system warning light
• Reduced power or limited hybrid operation
• Possible power-electronics overheating warning

How to diagnose it

1. Capture freeze-frame data and check pump B command, speed feedback, and power-electronics temperature data for evidence of a stall.
2. Check coolant level and inspect the branch for leaks or air that could prevent pump B from operating correctly.
3. With the vehicle safely powered down as specified, inspect pump B and its connector for visible damage, obstruction, or coolant intrusion.
4. Inspect and test pump B's power, control, and feedback wiring for loose connections, opens, or shorts against the manufacturer's specification.
5. If coolant supply and wiring are sound, test pump B and its driver using the manufacturer's procedure.

Common fixes

• Repair a leak and restore the specified coolant level.
• Bleed air from pump B's branch using the vehicle's procedure.
• Repair damaged or loose wiring and connector terminals at pump B.
• Replace a pump B motor or driver confirmed to be stalled or failed.

Can I keep driving?

Do not continue normal driving if pump B is confirmed stalled; without circulation, power electronics can overheat and the vehicle may reduce or disable hybrid output. If a temperature warning or power limit appears, stop safely and arrange service.