Motor Electronics Coolant Pump "A" Control Circuit Low
The P0A06 code means the vehicle's onboard diagnostic system has detected: Motor Electronics Coolant Pump "A" Control Circuit Low. This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $800 (relay/wiring at the low end; electric coolant pump replacement at the high end)
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Common Symptoms
- Check Engine Light on
- Inverter or motor electronics running hotter than normal
- Overtemperature codes may follow if driven with the pump inoperative
- No coolant flow noise/movement in the electronics loop reservoir
Probable Causes (Ranked by Likelihood)
- Failed Motor Electronics Coolant Pump "A" Very High
- Open or shorted pump control wiring, or a corroded connector High
- Blown fuse or failed relay feeding the pump Moderate
- Control-module driver fault Low
Frequently Asked Questions
What does P0A06 mean?
P0A06 means the control circuit for the Motor Electronics Coolant Pump "A" is faulty. This pump circulates coolant through the inverter/motor electronics loop - separate from the engine's cooling system on most hybrids.
Can I keep driving with P0A06?
Short distances only, and gently. The power electronics can overheat quickly without their pump, and an inverter failure costs far more than a pump.
Is P0A06 safe to work on myself?
This code involves the high-voltage system. Do not open the HV battery, inverter, or any orange-cabled component without hybrid-specific training, insulated gloves, and the service plug removed. Diagnosis beyond a scan-tool read belongs at a hybrid-qualified shop.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Command the Motor Electronics Coolant Pump "A" on with a scan tool and confirm it actually runs and moves coolant (watch the reservoir).
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Check power, ground, and the control signal at the pump connector.
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Check the pump fuse and relay.
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Bleed air from the electronics cooling loop after any repair - an airlocked pump reports faults and cools nothing.
-
Confirm normal inverter temperatures on a road test.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- Toyota/Lexus hybrids (Prius, Camry Hybrid, RAV4 Hybrid)
- Ford/Lincoln hybrids (Escape, Fusion, C-MAX)
- Honda hybrids (Insight, Civic Hybrid, Accord Hybrid)
- Hyundai/Kia hybrids and plug-in hybrids
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