TOYOTA TUNDRA 2021 Owners Manual (in English)

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When trouble arises
7-2. Steps to take in an emergency
If the engine will not star t
One of the following may be the cause of the problem:
● There may not be sufficient f uel in the vehicle’s tank.
Refuel the vehicle.
● The engine may be flooded.
Try to restart the engine again following correct starting proc edures.
(  P. 217)
● There may be a malf unction in the engine immobilizer system.
(  P. 8 5 )
One of the following may be the cause of the problem:
● The battery may be discharged. ( P. 525)
● The battery terminal connecti ons may be loose or corroded.
The engine starting system may be malfunctioning due to an elec trical
problem such as an open circuit or a blown fuse. However, an in terim
measure is available to start the engine. ( P. 522)
If the engine will not start eve n though correct starting proce -
dures are being followed ( P. 217), consider each of the follow-
ing points.
The engine will not start even t hough the starter motor operates
normally.
The starter motor turns over slowly, the interior lights and he ad-
lights are dim, or the horn does not sound or sounds at a low
volume.
The starter motor does not turn over (vehicles with a smart key
system)

5227-2. Steps to take in an emergency
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. 525)
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 ACC.
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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When trouble arises
7-2. Steps to take in an emergency
If the electronic key does not operate
properly (vehicles with a smar t key system)
Use the mechanical key (P. 122)
in order to perform the following
operations:
Locks all the doors
Unlocks all the doors
Turning the key rearward unlocks
the driver’s door. Turning the key
once again unlocks the other
doors.
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.
If any of the doors is opened or
closed while the key is being
touched to the switch, an alarm will
sound to indicate that the start
function cannot detect the key.
Press the engine switch.
In the event that the engine still cannot be started, contact your Toyota
dealer.
If communication between the electronic key and vehicle is
interrupted ( P. 142) 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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Starting the engine
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5247-2. Steps to take in an emergency
■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. 451)
■ 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. 220)

525
7
When trouble arises
7-2. Steps to take in an emergency
If the vehicle batter y is discharged
If you have a set of jumper (or booster) cables and a second ve hicle
with a 12-volt battery, you can jump start your vehicle by foll owing the
steps below.
Confirm that the key is being
carried.
When connecting the jumper (or
booster) cables, depending on the
situation, the alarm may activate
and the doors may lock. ( P. 96)
Open the hood. (P. 414)
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.
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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5267-2. Steps to take in an emergency
Connect a negative cable clamp to the negative (-) battery termi-
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 ON.
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.
■ 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 .
■ When the battery is r emoved or discharged
The moon roof must be initialized. ( P. 181)
■ 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.)
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5277-2. Steps to take in an emergency
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When trouble arises
■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 mem orized 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 discon necting 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.
WARNING
■ Avoiding battery fires or explosions
Observe the following precautions to prevent accidentally ignit ing the flam-
mable gas that may be emitted from the battery:
● Make sure each jumper cable is connected to the correct terminal and that
it is not unintentionally in contact with any other than the in tended terminal.
● 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 fla me near
the battery.
■ Battery precautions
The battery contains poisonous and corrosive acidic electrolyte , while
related parts contain lead and lead compounds. Observe the foll owing pre-
cautions when handling the battery:
● When working with the battery, always wear safety glasses and t ake care
not to allow any battery fluids (acid) to come into contact wit h skin, clothing
or the vehicle body.
● Do not lean over the battery.
● In the event that 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 medica l attention
can be received.
● Always wash your hands after handling the battery support, term inals, and
other battery-related parts.
● Do not allow children near the battery.

5287-2. Steps to take in an emergency
NOTICE
■When handling jumper cables
When connecting the jumper cables, ensure that they do not beco me entan-
gled in the cooling fan or belt.

529
7
When trouble arises
7-2. Steps to take in an emergency
If your vehicle overheats
●The needle of the engine coolant temperature gauge ( P. 1 0 5 )
enters the red zone or a loss of engine power is experienced. ( For
example, the vehicle speed does not increase.)
● “ENGINE COOLANT OVERTEMP” is shown on the multi-informa-
tion display.
● Steam comes out f rom under the hood.
Stop the vehicle in a safe place and turn off the air condition ing sys-
tem, and then stop the engine.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the engine has cooled
down sufficiently, inspect the
hoses and radiator core (radia-
tor) for any leaks. Radiator
Cooling fan
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
The following may indicate that your vehicle is overheating:
Correction procedures
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5307-2. Steps to take in an emergency
The coolant level is satisfactory
if it is between the “FULL” and
“LOW” lines on the reservoir.Reservoir
“FULL”
“LOW”
Radiator cap
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
Start the engine to check that the radiator cooling fan operate s and
to check for coolant leaks from the radiator or hoses.
If the fan is not operating:
Stop the engine immediately and contact your Toyota dealer.
If the fan is operating:
Have the vehicle ins pected at the nearest Toyota dealer.
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