DTC P1555-181: Reactor Temperature Sensor Circuit Low; DTC P1556-182: Reactor Temperature Sensor Circuit High: Description

The MG ECU located in the inverter with converter assembly detects the temperature of the reactor using a temperature sensor built into the inverter with converter assembly. The inverter cooling system is the same as that for MG2 and MG1, and it operates independently of the engine cooling system. The MG ECU uses signals from the reactor temperature sensor to check the effectiveness of the inverter cooling system. If necessary, the MG ECU will limit inverter output to help prevent inverter overheating. The MG ECU also detects malfunctions in the reactor temperature sensor and sends failure information to the hybrid vehicle control ECU which sets the following DTCs.

HINT: 

The reactor is a component with characteristics that resist changes in the current flow. The reactor will attempt to maintain the current flow. This characteristic stabilizes the current flowing to the HV battery. The reactor is also used to boost the HV battery voltage which is supplied to the inverters.