P0A02 critical

Motor Electronics Coolant Pump Control Circuit/Open

The P0A02 code means the vehicle's onboard diagnostic system has detected: Motor Electronics Coolant Pump Control Circuit/Open. This is a critical severity code.

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Keep driving?: Short distances only
DIY difficulty: hard
Estimated cost: $200 - $600 (parts and labor)

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Common Symptoms

Check Engine Light on
Hybrid system warning light
Motor electronics overheating warning
Reduced power or limp mode

Probable Causes (Ranked by Likelihood)

Failed motor electronics coolant pump Very High
Open circuit in pump control wiring High
Blown fuse for coolant pump circuit Moderate
Failed hybrid control module pump driver Low

Step-by-Step Diagnostic Procedure

Check the fuse for the motor electronics coolant pump circuit.
Test for battery voltage at the coolant pump connector with the pump commanded on.
Measure pump motor resistance to check for an open winding.
Inspect wiring harness from the control module to the pump for breaks or damage.

Frequently Asked Questions

Is P0A02 serious?

Yes, P0A02 is a critical code. Without the coolant pump functioning, motor electronics can overheat rapidly, potentially causing thousands of dollars in damage to the inverter and power electronics.

Can I drive with P0A02?

Drive only to the nearest repair facility. Without the coolant pump, the motor electronics will overheat under load. Continuing to drive risks severe damage to the hybrid inverter.

What is the motor electronics coolant pump?

It is an electric pump that circulates coolant through the hybrid motor electronics, inverter, and related components. It is separate from the engine water pump.