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 or MG1, and operates independently of the engine cooling system. The MG ECU limits the load based on signals sent from the reactor temperature sensor in order to check the effect of the inverter cooling system and prevent overheating. The ECU also detects malfunctions in the reactor temperature sensor.

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 battery voltage which is supplied to the inverters.