P0A05 on Toyota
Motor Electronics Coolant Pump "A" Control Circuit/Open
P0A05 on Toyota vehicles indicates motor electronics coolant pump "a" control circuit/open. Au7o has documented this code across 1 Toyota model — most commonly on Highlander. The control circuit for the motor electronics (inverter) coolant pump 'A' is open or not responding as commanded. This electric pump circulates coolant through the inverter/power-electronics loop. Typical repair costs on Toyota range from $700 to $1,100, depending on the specific model and root cause.
Common Causes of P0A05
- •Failed electric coolant pump
- •Open in pump control wiring/connector
- •Blown fuse or relay
- •Control module driver fault
P0A05 on Toyota by Model
Toyota Highlander(1 issue)
- Hybrid Inverter Coolant Pump Failure (Inverter Overheat) — P0A05 / P0A932006-2019
The Highlander Hybrid uses a dedicated electric water pump to circulate coolant through the power inverter/converter, which runs separately from the engine cooling system. The electric pump wears out and stops circulating coolant, allowing the inverter and hybrid electronics to overheat. Failures often present with little warning beyond a check engine light and hybrid warning lights; if ignored, the inverter itself (a far more expensive component) can be damaged. Owners report this most on the 2006-2010 generation but it recurs across later hybrids.
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View P0A05 across all makes →Frequently Asked Questions
What does P0A05 mean on Toyota?▼
P0A05 stands for "Motor Electronics Coolant Pump "A" Control Circuit/Open." The control circuit for the motor electronics (inverter) coolant pump 'A' is open or not responding as commanded. This electric pump circulates coolant through the inverter/power-electronics loop. On Toyota specifically, this code is documented across 1 model.
What causes P0A05 on Toyota vehicles?▼
Common causes on Toyota: Failed electric coolant pump, Open in pump control wiring/connector, Blown fuse or relay, Control module driver fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0A05 on a Toyota?▼
Repair costs on Toyota range from $700 to $1,100, depending on the specific model and root cause.
Which Toyota models have P0A05 documented?▼
Au7o has documented P0A05 on 1 Toyota model: Highlander.