What it means
The inverter B cooling system is not providing the expected cooling performance. Reduced coolant flow or another cooling-system fault may cause the inverter to limit output.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Inverter B's cooling system removes heat from the inverter so it can convert electrical power safely. The control system monitors cooling performance, including available temperature and flow information. This code sets when inverter B is not being cooled as expected, which can result from low coolant, restricted flow, a pump or fan fault, or a flow-control problem.
Common causes
Most likely first.
- Low coolant or air in the cooling circuit
- Faulty coolant pump
- Restricted coolant passage or heat exchanger
- Cooling fan or flow-control fault
Symptoms
- Hybrid/EV warning light may illuminate
- Reduced electric power or torque
- Inverter temperature warning may appear
How to diagnose it
- Save freeze-frame data and review inverter B temperature and cooling-system live data for signs of overheating or reduced flow.
- With the vehicle cool and following the owner's manual, check the inverter cooling circuit coolant level and look for visible leaks.
- Inspect accessible hoses, connectors, and wiring for inverter B's coolant pump, fan, and flow-control components for damage or loose connections.
- If supported by the scan tool, command the inverter B coolant pump and fan and check for operation and coolant circulation.
- Check for air, restrictions, or a blocked heat exchanger using the manufacturer's cooling-system procedure.
- If flow and components appear normal, compare temperature and flow sensor readings with manufacturer diagnostics to identify a sensing or control fault.
Common fixes
- Correct low coolant and repair any confirmed leak using the specified coolant and procedure.
- Bleed trapped air from inverter B's cooling circuit according to the manufacturer's procedure.
- Repair damaged wiring or connectors to the pump, fan, or flow-control components.
- Replace a failed coolant pump or fan, or clear a confirmed coolant passage restriction.
- Repair a faulty sensor or control component only if testing confirms it is causing the performance code.
Can I keep driving?
If an inverter temperature warning appears or electric power drops, stop safely and let the system cool; continued operation can overheat and damage inverter components. If there is no warning or power reduction, drive only as needed and arrange prompt diagnosis.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.