Motor Electronics Coolant Pump B Control Performance
What it means
The module compared the commanded speed or flow of motor electronics coolant pump B with what it actually achieves, and they do not match. Either the pump is weak or stuck, or the coolant flow is blocked.
Can I keep driving? Use caution: hybrid and electric systems may limit power or shut down, and high-voltage faults are not for roadside fixes, so get it checked soon.
What this part does
The power electronics coolant pump circulates coolant through the inverter and other power electronics of a hybrid or electric vehicle to carry heat away. The control module runs it based on temperature so the electronics stay within safe limits. These parts operate at high voltage, so work on them is for trained people. A fault may lead to a warning, reduced power or overheating protection.
Common symptoms
What you'll notice
- Hybrid warning light on
- Reduced power from overheating protection
- Cooling fan running hard
Common causes
Most likely first
- Low coolant or air in the cooling loop
- Weak or worn pump
- Wiring or connector fault at the pump
- Blocked coolant line or radiator
- Control module fault
How to diagnose & fix
Work through it in order
- Read all codes, including coolant temperature codes.
- Check the electronics coolant level if the reservoir is reachable.
- Confirm the pump runs and is not noisy or silent when commanded.
- Inspect the pump connector and wiring.
- Check for blockage or kinked lines before replacing the pump.
Related codes
Read & clear P0C74 yourself
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