P0A78 on Nissan
Drive Motor A Inverter Over-Temperature
P0A78 on Nissan vehicles indicates drive motor a inverter over-temperature. Au7o has documented this code across 1 Nissan model — most commonly on Leaf. P0A78 is a hybrid/electric-vehicle code indicating that drive motor 'A' inverter has overheated. The inverter converts the high-voltage battery's DC power into AC to drive the electric traction motor, and it has temperature sensors; when the inverter temperature exceeds safe limits, the control module sets this code and usually reduces power to protect the components. Symptoms include reduced power (limp mode), warning lights, or in severe cases the vehicle refusing to drive. It points to an inverter cooling or electronics problem in the high-voltage drive system rather than the gasoline engine. Typical repair costs on Nissan range from $1,500 to $6,000, depending on the specific model and root cause.
Common Causes of P0A78
- •Low coolant or air in the inverter cooling loop
- •Failed inverter/electronics coolant pump
- •Clogged or restricted inverter cooling passages/radiator
- •Faulty inverter temperature sensor
- •Failed or degrading inverter/power module
- •Cooling fan or thermostat fault in the inverter loop
- •Excessive load or related high-voltage system fault
P0A78 on Nissan by Model
Nissan Leaf(1 issue)
- Traction Motor Inverter Failure2011-2017
The 2011-2017 Leaf traction motor inverter can fail, resulting in complete loss of propulsion. The inverter converts DC battery power to AC for the motor. Symptoms include sudden power loss, error messages, and the vehicle going into turtle mode. This is a costly repair outside warranty.
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View P0A78 across all makes →Frequently Asked Questions
What does P0A78 mean on Nissan?▼
P0A78 stands for "Drive Motor A Inverter Over-Temperature." P0A78 is a hybrid/electric-vehicle code indicating that drive motor 'A' inverter has overheated. The inverter converts the high-voltage battery's DC power into AC to drive the electric traction motor, and it has temperature sensors; when the inverter temperature exceeds safe limits, the control module sets this code and usually reduces power to protect the components. Symptoms include reduced power (limp mode), warning lights, or in severe cases the vehicle refusing to drive. It points to an inverter cooling or electronics problem in the high-voltage drive system rather than the gasoline engine. On Nissan specifically, this code is documented across 1 model.
What causes P0A78 on Nissan vehicles?▼
Common causes on Nissan: Low coolant or air in the inverter cooling loop, Failed inverter/electronics coolant pump, Clogged or restricted inverter cooling passages/radiator, Faulty inverter temperature sensor, Failed or degrading inverter/power module. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0A78 on a Nissan?▼
Repair costs on Nissan range from $1,500 to $6,000, depending on the specific model and root cause.
Which Nissan models have P0A78 documented?▼
Au7o has documented P0A78 on 1 Nissan model: Leaf.