2021 TOYOTA 4RUNNER key battery

5057-2. Steps to take in an emergency
7
When trouble arises
4RUNNER (U)
One of the following may be the cause of the problem:
● One or both of the battery t erminals may be disconnected.
● The battery may be discharged. ( P. 510)
● There may be a malfunction in the steering lock system (vehicles
with a smart key system).
Contact your Toyota dealer if the problem cannot be repaired, o r if repair
procedures are unknown.
When the engine does not start, the following steps can be used as an
interim measure to start the engine if the engine switch is fun ctioning
normally:
Set the parking brake.
Shift the shift lever to P.
Turn the engine switch to ACCESSORY mode.
Press and hold the engine switch for about 15 seconds while
depressing the brake pedal firmly.
Even if the engine can be start ed using the above steps, the sy stem
may be malfunctioning. Have the vehicle inspected by your Toyot a
dealer.
The starter motor does not turn over, the interior lights and h ead-
lights do not turn on, o r the horn does not sound.
Emergency start function (vehicles with a smart key system)
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5077-2. Steps to take in an emergency
7
When trouble arises
4RUNNER (U)
Use the mechanical key
( P. 104) in order to perform the
following operations:
Locks all the doors
Closes the windows and moon
roof (turn and hold)
*
(  P. 164, 172)
Unlocks all the doors
Turning the key rearward unlocks the driver’s door. Turning the key once
again unlocks the other doors.
Opens the windows and moon roof (turn and hold)*
(  P. 164, 172)
*: This setting must be customized at your Toyota dealer.
If the electronic key does not operate
properly (vehicles with a smar t key system)
If communication between the electronic key and vehicle is
interrupted ( P. 122) or the electronic key cannot be used
because the battery is depleted, the smart key system and wire-
less remote control cannot be used. In such cases, the doors
can be opened and the engine c an be started by following the
procedure below.
Locking and unlocking the doors
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5087-2. Steps to take in an emergency
4RUNNER (U)
Ensure that the shift lever is in P and depress the brake pedal.
Touch the Toyota emblem side
of the electronic key to the
engine switch.
When the electronic key is
detected, a buzzer sounds and the
engine switch will turn to IGNITION
ON mode.
When the smart key system is
deactivated in customization set-
ting, the engine switch will turn to
ACCESSORY mode.
Firmly depress the brake pedal and check that is displayed
on the multi-information display.
Press the engine switch shortly and firmly.
In the event that the engine still cannot be started, contact your Toyota
dealer.
■ Stopping the engine
Shift the shift lever to P and press the engine switch as you normally do when
stopping the engine.
■ Replacing the key battery
As the above procedure is a temporary measure, it is recommende d that the
electronic key battery be replaced immediately when the battery is depleted.
( P. 444)
■ Changing engine switch modes
Within 10 seconds of the buzzer sounding, release the brake ped al and press
the engine switch.
The engine does not start and modes will be changed each time t he switch is
pressed.( P. 213)
■ When the electronic key does not work properly
●Make sure that the smart key system has not been deactivated in the cus-
tomization setting. If it is off, turn the function on.
(Customizable features: P. 545)
● Check if battery-saving mode is set. If it is set, cancel the f unction.
( P. 121)
Starting the engine
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5107-2. Steps to take in an emergency
4RUNNER (U)
If you have a set of jumper (or booster) cables and a second vehicle
with a 12-volt battery, you can jump start your vehicle by foll owing the
steps below.
Confirm that the electronic key
is being carried.
When connecting the jumper (or
booster) cables, depending on the
situation, the alarm may activate
and doors locked. ( P. 80)
Open the hood ( P. 407)
If the vehicle batt er y is discharged
The following procedures may be used to start the engine if the
vehicle’s battery is discharged.
You can also call your Toyota de aler or a qualified repair shop.
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5117-2. Steps to take in an emergency
7
When trouble arises
4RUNNER (U)
Connect the jumper cables according to the following procedure:Connect a positive jumper cable clamp to the positive (+) batte ry
terminal on your vehicle.
Connect the clamp on the other end of the positive cable to the
positive (+) battery termi nal on the second vehicle.
Connect a negative cable clamp to the negative (-) battery term i-
nal on the s econd vehicle.
Connect the clamp at the other e nd of the negative cable to a
solid, stationary, unpainted meta llic point away from the battery
and any moving parts, as shown in the illustration.
Start the engine of the second v ehicle. Increase the engine speed
slightly and maintain at that lev el for approximately 5 minutes to
recharge the batter y of your vehicle.
Vehicles with a smart key system only: Open and close any of th e
doors of your vehicle wi th the engine switch off.
Maintain the engine speed of the second vehicle and start the
engine of your vehicle by turning the engine switch to the “ON”
position (vehicles without a smart key system) or turning the e ngine
switch to IGNITION ON mode (vehi cles with a smart key system).
Once the vehicle’s engine has st arted, remove the jumper cables in
the exact reverse order from which they were connected.
Once the engine starts, have the vehicle inspected at your Toyota
dealer as soon as possible.3
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5127-2. Steps to take in an emergency
4RUNNER (U)
■Starting the engine when t he battery is discharged
The engine cannot be started by push-starting.
■ To prevent battery discharge
●Turn off the headlights and the audio system while the engine is off.
● Turn off any unnecessary electrical components when the vehicle is running
at a low speed for an extended period, such as in heavy traffic .
■ Charging the battery
The electricity stored in the battery will discharge gradually even when the
vehicle is not in use, due to natural discharge and the draining effects of cer-
tain electrical appliances. If the vehicle is left for a long t ime, the battery may
discharge, and the engine may be unable to start. (The battery recharges
automatically during driving.)
■ When recharging or replacing the battery
●Vehicles with a smart key system: In some cases, it may not be possible to
unlock the doors using the smart key system when the battery is dis-
charged. Use the wireless remote control or the mechanical key to lock or
unlock the doors.
● The engine may not start on the first attempt after the battery has recharged
but will start normally after the second attempt. This is not a malfunction.
● Vehicles with a smart key system: The engine switch mode is memorized by
the vehicle. When the battery is reconnected, the system will r eturn to the
mode it was in before the battery was discharged. Before disconnecting the
battery, turn the engine switch off.
If you are unsure what mode the engine switch was in before the battery dis-
charged, be especially careful when reconnecting the battery.
● Make sure that the key is not inside the vehicle when rechargin g or replac-
ing the battery. The key may be locked in the vehicle if the al arm is acti-
vated. ( P. 80)

5578-2. Customization
8
Vehicle specifications
4RUNNER (U)
■In the following situations, customize mode will automatically be turned
off.
● A warning message appears after the customize mode screen is di splayed.
● The engine switch is turned to the “LOCK” position (without a s mart key sys-
tem) or the engine switch is turned to OFF (with a smart key sy stem).
● The vehicle begins to move while the customize mode screen is d isplayed.
WARNING
■During customization
As the engine needs to be running during customization, ensure that the
vehicle is parked in a place with adequate ventilation. In a closed area such
as a garage, exhaust gases including harmful carbon monoxide (CO) may
collect and enter the vehicle. This may lead to death or a seri ous health
hazard.
NOTICE
■ During customization
To prevent battery discharge, ensure that the engine is running while cus-
tomizing features.

574
4RUNNER (U)
What to do if... (Troubleshooting)
What to do if... (Troubleshooting)
●If you lose your keys or mechanical keys, new genuine mechanical keys
can be made by your Toyota dealer. ( P. 105)
●If you lose your keys or electronic keys, the risk of vehicle t heft increases
significantly. Contact your Toyota dealer immediately. ( P. 109)
●Is the key battery weak or depleted? (P. 443)
●Vehicles with a smart key system:
Is the engine switch in IGNITION ON mode?
When locking the doors, turn the engine switch off. ( P. 213)
●Vehicles with a smart key system:
Is the electronic key left inside the vehicle?
When locking the doors, make sure that you have the electronic key on
your person.
●The function may not operate properly due to the condition of t he radio
wave. ( P. 122)
●Is the child-protector lock set?
The rear door cannot be opened from inside the vehicle when the lock is
set. Open the rear door from outside and then unlock the child-protector
lock. ( P. 114)
If you have a problem, check the following before contacting
your Toyota dealer.
The doors cannot be locked, unlocked, opened or closed
You lose your keys
The doors cannot be locked or unlocked
The rear door cannot be opened