P2D04: Motor Electronics Coolant Pump A Control Module Overtemperature

What it means

Motor electronics coolant pump A reports a control module overtemperature 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

Pump A's control module operates the motor electronics coolant pump and monitors its own temperature while controlling cooling flow. This code sets when that module detects an overtemperature condition, which may cause it to limit pump operation and reduce power-electronics cooling.

Common causes

Most likely first.

1. Ambient temperature too high
2. Module cooling path blocked

Symptoms

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

How to diagnose it

1. Read freeze-frame data and live pump A module temperature, pump command, and warning status to determine when the overtemperature occurs.
2. With the vehicle safely powered down, inspect pump A's module area for blocked airflow, debris, heat damage, or an obstructed cooling path.
3. Check the surrounding cooling path and coolant hoses for kinks, leaks, or other conditions that could prevent heat removal.
4. Check coolant level and evidence of poor circulation in the relevant loop, following the vehicle's safety and service instructions.
5. Compare module temperature and pump operation with the manufacturer's diagnostic procedure, especially when ambient conditions are not unusually hot.
6. If the cooling path is clear, test pump A's electrical supply and module operation as specified by the manufacturer.

Common fixes

• Clear debris or obstruction from pump A's module cooling path.
• Correct low coolant or a restriction affecting heat removal, then bleed the loop as specified.
• Repair damaged hoses or wiring that impair pump A cooling or operation.
• Replace pump A's control module or pump assembly if it continues to overheat with a clear cooling path and correct supply.

Can I keep driving?

Avoid high-load driving because pump A may not maintain enough cooling for the power electronics. If the vehicle limits power or displays a hybrid-system warning, stop safely and arrange prompt diagnosis.