P2D01: Motor Electronics Coolant Pump A Overspeed/Air in System

What it means

Motor electronics coolant pump A reports a overspeed/air in system condition. Power electronics cooling is impaired.

At a glance

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

How it works

Motor electronics coolant pump A circulates coolant through the power electronics cooling loop. The module monitors pump operation and sets this code when pump A appears to run too fast or the loop behaves as though it contains air, which can impair heat removal.

Common causes

Most likely first.

1. Air pocket in coolant loop
2. Coolant level low

Symptoms

• Check-engine or hybrid-system warning
• Power limited warning
• Reduced performance under load

How to diagnose it

1. Review freeze-frame data and live pump speed and loop temperature data to see when pump A reported overspeed.
2. With the system cool, check the motor electronics coolant level and inspect the loop for visible leaks.
3. Inspect pump A and its connectors for loose connections or damage that could disturb pump feedback.
4. Check the cooling loop for signs of trapped air and verify the system was filled and bled according to the manufacturer's procedure.
5. Test pump A speed feedback and operation against the manufacturer's procedure if the level and air condition are correct.

Common fixes

• Repair leaks and restore the motor electronics coolant level.
• Bleed trapped air from the loop using the manufacturer's procedure.
• Repair a loose or damaged pump A connector or wiring.
• Replace pump A if testing confirms faulty speed feedback or abnormal operation.

Can I keep driving?

Power may be limited if the motor electronics cooling loop cannot remove heat properly. Avoid heavy loads and stop if a temperature or power-limited warning appears, since continued driving can overheat the power electronics.