Motor Electronics Coolant Pump Motor Performance
The P0A05 code means the vehicle's onboard diagnostic system has detected: Motor Electronics Coolant Pump Motor Performance. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $200 - $550 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Hybrid system warning light
- Reduced coolant flow to motor electronics
- Higher than normal motor electronics temperatures
Probable Causes (Ranked by Likelihood)
- Worn or degraded coolant pump motor Very High
- Blocked or restricted coolant passages High
- Air trapped in motor electronics cooling circuit Moderate
- Low coolant level in motor electronics circuit Moderate
Step-by-Step Diagnostic Procedure
-
Check motor electronics coolant level and top off if low.
-
Bleed air from the motor electronics cooling circuit following manufacturer procedure.
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Command the pump on with a scan tool and verify coolant flow through the system.
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Measure pump current draw and compare to specification to check for a weak pump motor.
Frequently Asked Questions
What does pump motor performance mean in P0A05?
The hybrid control module has determined that the coolant pump is running but not performing to specification. The pump may be weak, or coolant flow may be restricted by blockages or air pockets.
Can I bleed the motor electronics coolant system myself?
Some hybrid vehicles have a straightforward bleed procedure, but many require specific scan tool commands to cycle the pump during bleeding. Consult your service manual.
How long do motor electronics coolant pumps last?
These pumps typically last 100,000 to 150,000 miles under normal conditions. Harsh climates and neglected coolant changes can shorten pump life significantly.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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