Lexus ES300h Owner's Manual page 529

If "Hybrid System Overheated" is shown on the multi-information display
■
Stop the vehicle in a safe place.
1
Stop the hybrid system and carefully lift the hood.
2
After the hybrid system has cooled down, inspect the hoses and radiator
3
core (radiator) for any leaks.
Radiator
1
Cooling fans
2
If a large amount of coolant leaks,
immediately contact your Lexus
dealer.
The coolant level is satisfactory if it is between the "FULL" and "LOW" line
4
on the reservoir.
Reservoir
1
"FULL"
2
"LOW"
3
Add coolant if necessary.
5
Water can be used in an emergency
if coolant is unavailable.
Start the hybrid system and check for the multi-information display.
6
If the message does not disappear:
Stop the hybrid system and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
ES300h_OM_OM33B71U_(U)
8-2. Steps to take in an emergency
529
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