Lexus HS 250h, Vehicle Dismantling Manual

High Voltage Safety 

The HV battery pack powers the high voltage electrical system with DC electricity.    Positive 
and negative orange colored high voltage power cables are routed from the battery pack, under 
the vehicle floor pan, to the inverter/converter.    The inverter/converter contains a circuit that 
boosts the HV battery voltage from 244.8 to 650 Volts DC.    The inverter/converter creates 
3-phase AC to power the motors.    Power cables are routed from the inverter/converter to each 
high voltage motor (front and rear electric motors, electric generator, and A/C compressor).   
The following systems are intended to help keep occupants in the vehicle and emergency 
responders safe from high voltage electricity:   

High Voltage Safety System     

• 

A high voltage fuse 

n

* provides short circuit protection in the HV battery pack.     

• 

Positive and negative high voltage power cables 

o

* connected to the HV battery pack are 

controlled by 12 Volt normally open relays 

p

*.    When the vehicle is shut off, the relays 

stop electricity flow from leaving the HV battery pack.     

WARNING:

・ 

The high voltage system may remain powered for up to 10 
minutes after the vehicle is shut off or disabled.    To prevent 
serious injury or death from severe burns or electric shock, 
avoid touching, cutting, or opening any orange high voltage 
power cable or high voltage component.     

• 

Both positive and negative power cables 

o

* are insulated from the metal chassis, so there is 

no possibility of electric shock when touching the metal chassis.     

• 

A ground-fault monitor continuously monitors for high voltage leakage to the metal chassis 
while the vehicle is running.    If a malfunction is detected, the hybrid vehicle computer 

q

* 

will illuminate the master warning light 

  in the instrument cluster and indicate 

“

CHECK HYBRID SYSTEM

” on the multi-information display.     

• 

The HV battery pack relays will automatically open to stop electricity flow in a collision 
sufficient to activate the SRS.     

 
*Numbers apply to the illustration on the following page.   

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