
3657-2. Steps to take in an emergency
7
When trouble arises
turning the engine switch 
8 Once the vehicle’s engine 
jumper cables in the exact reverse 
order from which they were con-
nected.
9 Close the exclusive jump starting 
terminal cover, and reinstall the fuse 
box cover to its original position.
Once the engine 
have the vehicle inspected at your Lexus 
dealer as soon as possible.
■Starting the engine 
when the 12-volt battery is discharged
The engine 
started by push-starting.
■To prevent 12-volt battery discharge
●Turn off the headlights and the audio sys-
tem while the engine 
stopped.
●Turn off any unnecessary electrical com-
ponents when the vehicle is running at a 
low speed for an extended period, such 
as in heavy traffic.
■When the 12-volt battery is removed or 
discharged
●Information stored in the ECU is cleared. 
When the 12-volt battery is depleted, 
have the vehicle inspected at your Lexus 
dealer.
●Some systems may require initialization. 
(  P.407)
■When removing the 12-volt battery ter-
minals
When the 12-volt battery terminals are 
removed, the information stored in the 
ECU is cleared. Before removing the 12-
volt battery terminals, contact your Lexus 
dealer.
■Charging the 12-volt battery
The electricity stored in the 12-volt battery 
will discharge gradually even when the 
vehicle is not in use, due to natural dis-
charge and the draining effects of certain 
electrical appliances. If the vehicle is left for 
a long time, the 12-volt battery may dis-
charge, and the engine 
may be unable to start. (The 12-volt battery 
recharges automatically during driving.)
■When recharging or replacing the 12-
volt battery
●In some cases, it may not be possible to 
unlock the doors using the smart access 
system with push-button start when the 
12-volt battery is discharged. Use the 
wireless remote control or the mechani-
cal key to lock or unlock the doors.
●The engine 
on the first attempt after the 12-volt bat-
tery has recharged but will start normally 
after the second attempt. This is not a 
malfunction.
●The engine switch 
is memorized by the vehicle. When the 
12-volt battery is reconnected, the system 
will return to the mode it was in before 
the 12-volt battery was discharged. 
Before disconnecting the 12-volt battery, 
turn the engine switch 
If you are unsure wh at mode the engine 
switch 
12-volt battery discharged, be especially 
careful when reconnecting the 12-volt 
battery.
●If the 12-volt battery discharges, it may 
not be possible to shift the shift position to 
other positions. In this case, the vehicle 
cannot be towed without lifting both rear 
wheels because the re ar wheels will be 
locked. ( P.334)
■When replacing the 12-volt battery
●Use a Central Degassing type 12-volt 
battery (European Regulations).
●Type A*1: Use a 12-volt battery that the 
case size is same  as the previous one 
(LN4), 20 hour rate capacity (20HR) is 
equivalent (80Ah) or greater, and per-
formance rating (CCA) is equivalent 
(685A) or greater.  

3667-2. Steps to take in an emergency
Type B*2: Use a 12-volt battery that the 
case size is same as the previous one 
(LN3), 20 hour rate capacity (20HR) is 
equivalent (70Ah) or greater, and perfor-
mance rating (CCA) is equivalent 
(600A) or greater.
• If the sizes differ, the 12-volt battery can-
not be properly secured.
• If the 20 hour rate capacity is low, even if  the time period where the vehicle is not 
used is a short time, the 12-volt battery 
may discharge and engine 
●Use a 12-volt battery with a handle. If a 
12-volt battery without a handle is used, 
removal is more difficult.
●After exchanging, firmly attach the fol-
lowing items to the exhaust hole of the 12-
volt battery.
• Use the exhaust hose that was attached 
to the 12-volt battery before exchanging.
• Use the exhaust hole plug included with  the 12-volt battery exchanged or the one 
installed on the battery prior to the 
exchange. (Depending on the 12-volt 
battery to be exchanged, the exhaust 
hole may be plugged.)
Exhaust hole plug
Exhaust hole
Exhaust hose
For details, consult your Lexus dealer.
*1: LC500 for Canada or LC500 with  heated steering wheel
*2: LC500 except for Canada, LC500 
without heated steering wheel or 
LC500h
A
B
C
WARNING
■When removing the 12-volt battery 
terminals
Always remove the negative (-) terminal 
first. If the positive (+) terminal contacts 
any metal in the surrounding area when 
the positive (+) terminal is removed, a 
spark may occur, leading to a fire in addi-
tion to electrical shocks and death or 
serious injury.
■Avoiding 12-volt battery fires or 
explosions
Observe the following precautions to 
prevent accidentally igniting the flamma-
ble gas that may be emitted from the 12-
volt battery:
●Make sure each jumper cable is con-
nected to the correct terminal and that 
it is not unintentionally in contact with 
any other than the intended terminal.
●Do not allow the other end of the 
jumper cable connected to the “+” ter-
minal to come into contact with any 
other parts or meta l surfaces in the 
area, such as brackets or unpainted 
metal.
●Do not allow the + and - clamps of the 
jumper cables to come into contact 
with each other.
●Do not smoke, use matches, cigarette 
lighters or allow open flame near the 
12-volt battery.
●If the 12-volt battery  fluid level is exces-
sively low ( P.305), do not use the 
12-volt battery. 

3677-2. Steps to take in an emergency
7
When trouble arises
WARNING
■12-volt battery precautions
The 12-volt battery contains poisonous 
and corrosive acidic electrolyte, while 
related parts contain lead and lead com-
pounds. Observe the following precau-
tions when handling the 12-volt battery:
●When working with the 12-volt battery, 
always wear safety  glasses and take 
care not to allow any 12-volt battery 
fluids (acid) to come into contact with 
skin, clothing or the vehicle body.
●Do not lean over the 12-volt battery.
●In the event that 12-volt battery fluid 
comes into contact with the skin or 
eyes, immediately wash the affected 
area with water and seek medical 
attention.
Place a wet sponge or cloth over the 
affected area until medical attention 
can be received.
●Always wash your hands after handling 
the 12-volt battery support, terminals, 
and other batter y-related parts.
●Do not allow children near the 12-volt 
battery.
■After recharging the 12-volt battery
Have the 12-volt battery inspected at 
your Lexus dealer as soon as possible. If 
the 12-volt battery is deteriorating, con-
tinued use may cause the 12-volt battery 
to emit a malodorous gas, which may be 
detrimental to the health of passengers.
■When exchanging the 12-volt battery
After exchanging, securely attach the 
exhaust hose and exhaust hole plug to 
the exhaust hole of the exchanged 12-
volt battery. If not properly installed, 
gases (hydrogen) may leak into the vehi-
cle interior, and there is the possible dan-
ger of the gas igniting and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper cables, 
ensure that they do not become entan-
gled in the cooling fan or engine drive 
belt.
■To prevent damaging the vehicle
The exclusive jump starting terminal is to 
be used when charging the 12-volt bat-
tery from another vehicle in an emer-
gency. It cannot be used to jump start 
another vehicle.