2021 TOYOTA TUNDRA engine overheat

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6-1. Maintenance and careCleaning and protecting the vehicle exterior .......... 400
Cleaning and protecting the vehicle interior ........... 403
6-2. Maintenance Maintenance requirements ................... 406
General maintenance ........ 408
Emission inspection and maintenance (I/M)
programs ......................... 411
6-3. Do-it-yourself maintenance Do-it-yourself service precautions ..................... 412
Hood.................................. 414
Engine compartment ......... 415
Tires .................................. 426
Tire inflation pressure........ 442
Wheels .............................. 445
Air conditioning filter .......... 448
Wireless remote control/ electronic key battery ...... 451
Checking and replacing fuses ............................... 454
Light bulbs ......................... 457 7-1. Essential information
Emergency flashers ........... 474
If your vehicle has to be stopped in
an emergency.................. 475
If the vehicle is trapped in rising water .................. 477
7-2. Steps to take in an emergency
If your vehicle needs to be towed .......................... 478
If you think something is wrong............................... 483
Fuel pump shut off system ............................. 484
If a warning light turns on or a warning buzzer
sounds ............................. 485
If a warning message is displayed ......................... 493
If you have a flat tire .......... 506
If the engine will not start ................................. 521
If the electronic key does not operate properly
(vehicles with a smart
key system) .................... 523
If the vehicle battery is discharged ....................... 525
If your vehicle overheats.... 529
If the vehicle becomes stuck ................................ 532
6Maintenance and care7When trouble arises

17Pictorial index
Fuel filler door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 248
Refueling method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 248
Fuel type/fuel tank capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 542
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 426
Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 548
Winter tires/tire chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 331
Checking/rotation/tire pressure warning system . . . . . . . . . . . P. 426
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 506
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 414
Opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 414
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 543
Coping with overheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 529
Camera
*4
Headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 234
Fog lights
*3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 244
Front turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 232
Parking lights/daytime running lights . . . . . . . . . . . . . . . . . P. 234
Rear turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 232
Tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 234
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 234
Back-up lights
Shifting the shift lever to R . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 225
Side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 234
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Light bulbs of the exter ior lights for driving
(Replacing method: P. 457, Watts: P. 550)
*1: Vehicles with a smart key system
*2: If equipped on CrewMax models
*3: If equipped
*4: Refer to the “NAVIGATION AND MULTIMEDIA
SYSTEM OWNER’S MANUAL”.
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1092. Instrument cluster
2
Instrument cluster
NOTICE
■To prevent damage to the engine and its components
● Do not let the indicator needle of the tachometer enter the red zone, which
indicates the maximum engine speed.
● The engine may be overheating if the engine coolant temperature gauge is
in the red zone (H). In this case, immediately stop the vehicle in a safe
place, and check the engine after it has cooled completely. ( P. 5 2 9 )
■ Vo l t m e t e r
When the voltmeter indicates 19 V or higher or 9 V or lower whi le the engine
is running, there may be a battery or charging system malfunction. Have the
vehicle inspected at your Toyota dealer.
■ Engine oil pressure gauge
When the value of the engine oil pressure gauge drops while the engine is
running, stop the vehicle in a safe place immediately and check the amount
of engine oil. ( P. 416)
When the oil pressure drops even though the engine oil amount h as not
decreased, or if the oil pressure does not increase when engine oil is
added, contact your Toyota dealer, as there may be a problem wi th the lubri-
cation system.

1874-1. Before driving
4
Driving
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When starting the vehicle
Always keep your foot on the brake pedal while stopped with the engine
running. This prevents the vehicle from creeping.
■ When driving the vehicle
● Do not drive if you are unfamiliar with the location of the brake and accel-
erator pedals to avoid depressing the wrong pedal.
• Accidentally depressing the accelerator pedal instead of the b rake
pedal will result in sudden acceleration that may lead to an accident.
• When backing up, you may twist your body around, leading to di fficulty
in operating the pedals. Make sure to operate the pedals proper ly.
• Make sure to keep a correct driving posture even when moving t he
vehicle only slightly. This allows you to depress the brake and accelera-
tor pedals properly.
• Depress the brake pedal using your right foot. Depressing the brake
pedal using your left foot may delay response in an emergency, result-
ing in an accident.
● Do not drive the vehicle over or stop the vehicle near flammable materials.
The exhaust system and exhaust gases can be extremely hot. Thes e hot
parts may cause a fire if there is any flammable material nearby.
● During normal driving, do not turn off the engine. Turning the engine off
while driving will not cause loss of steering or braking contro l, but the
power assist to these systems will be lost. This will make it m ore difficult to
steer and brake, so you should pull over and stop the vehicle a s soon as it
is safe to do so.
However, in the event of an emergency, such as if it becomes im possible
to stop the vehicle in the normal way: P. 475
● Use engine braking (downshift) to maintain a safe speed when driving
down a steep hill.
Using the brakes continuously may cause the brakes to overheat and lose
effectiveness. ( P. 225)
● Do not adjust the positions of the steering wheel, the seat, or the inside or
outside rear view mirrors while driving.
Doing so may result in a loss of vehicle control.
● Always check that all passengers’ arms, heads or other parts of their body
are not outside the vehicle.

1894-1. Before driving
4
Driving
WARNING
■If you hear a squealing or scrap ing noise (brake pad wear limit indica-
tors)
Have the brake pads checked and replaced by your Toyota dealer as soon
as possible.
Rotor damage may result if the pads are not replaced when neede d.
It is dangerous to drive the vehicle when the wear limits of the brake pads
and/or those of the brake discs are exceeded.
■ When the vehicle is stopped
● Do not race the engine.
If the vehicle is in any gear other than P or N, the vehicle may move sud-
denly and unexpectedly, causing an accident.
● In order to prevent accidents due to the vehicle rolling away, always keep
depressing the brake pedal while the engine is running, and app ly the
parking brake as necessary.
● If the vehicle is stopped on an incline, in order to prevent ac cidents caused
by the vehicle rolling forward or backward, always depress the brake pedal
and securely apply the parking brake as needed.
● Avoid revving or racing the engine.
Running the engine at high speed while the vehicle is stopped m ay cause
the exhaust system to overheat, which could result in a fire if combustible
material is nearby.
■ When the vehicle is parked
● Do not leave glasses, cigarette lighters, spray cans, or soft d rink cans in
the vehicle when it is in the sun.
Doing so may result in the following:
• Gas may leak from a cigarette lighter or spray can, and may le ad to a
fire.
• The temperature inside the vehicle may cause the plastic lenses and plastic material of glasses to deform or crack.
• Soft drink cans may rupture, causing the contents to spray ove r the
interior of the vehicle, and may also cause a short circuit in the vehicle’s
electrical components.
● Do not leave cigarette lighters in the vehicle. If a cigarette lighter is in a
place such as the glove box or on the floor, it may be lit acci dentally when
luggage is loaded or the seat is adjusted, causing a fire.
● Do not attach adhesive discs to the windshield or windows. Do n ot place
containers such as air fresheners on the instrument panel or da shboard.
Adhesive discs or containers may act as lenses, causing a fire in the vehi-
cle.

1904-1. Before driving
WARNING
●Do not leave a door or window open if the curved glass is coate d with a
metallized film such as a silver-colored one. Reflected sunligh t may cause
the glass to act as a lens, causing a fire.
● Always apply the parking brake, shift the shift lever to P, stop the engine
and lock the vehicle.
Do not leave the vehicle unattended while the engine is running .
If the vehicle is parked with the shift lever in P but the park ing brake is not
set, the vehicle may start to move, possibly leading to an acci dent.
● Do not touch the exhaust pipes while the engine is running or i mmediately
after turning the engine off.
Doing so may cause burns.
● 4WD models: If the shift lever is moved before the “4LO” indicator turns
on/off, the transfer mode may not be shifted completely. The tr ansfer mode
disengages both the front and rear driveshafts from the powertrain and
allows the vehicle to move regardless of the shift position. (A t this time, the
indicator blinks and the buzzer sounds.)
Therefore, the vehicle is free to roll even if the automatic transmission is in
P. You or someone else could be seriously injured. You must complete the
shifting of the transfer mode. ( P. 315)
■ When taking a nap in the vehicle
Always turn the engine off. Otherwise, if you accidentally move the shift
lever or depress the accelerator pedal, this could cause an acc ident or fire
due to engine overheating. Additionally, if the vehicle is park ed in a poorly
ventilated area, exhaust gases may collect and enter the vehicl e, leading to
death or a serious health hazard.
■ When braking
● When the brakes are wet, drive more cautiously.
Braking distance increases when the brakes are wet, and this ma y cause
one side of the vehicle to brake differently than the other sid e. Also, the
parking brake may not securely hold the vehicle.
● If the brake booster device does not operate, do not follow oth er vehicles
closely and avoid hills or shar p turns that require braking.
In this case, braking is still possible, but the brake pedal sh ould be
depressed more firmly than usual. Also, the braking distance wi ll increase.
Have your brakes fixed immediately.
● Do not pump the brake pedal if the engine stalls.
Each push on the brake pedal uses up the reserve for the power-assisted
brakes.
● The brake system consists of 2 individual hydraulic systems; if one of the
systems fails, the other will still operate. In this case, the brake pedal
should be depressed more firmly than usual and the braking dist ance will
increase. Have your brakes fixed immediately.

2104-1. Before driving
●Avoid sudden braking as you may skid, resulting in the trailer jack-
knifing and a loss of vehicle control. This is especially true on wet or
slippery surfaces.
● Avoid jerky starts or sudden acceleration.
● Avoid jerky steering and sharp turns, and slow down before maki ng
a turn.
● Note that when making a turn, the trailer wheels will be closer than
the vehicle wheels to the inside of the turn. Compensate by mak ing
a wider than normal turning radius.
● Slow down before making a turn, in crosswinds, on wet or slippe ry
surfaces, etc.
Increasing vehicle speed can destabilize the trailer.
● Take care when passing other vehicles. Passing requires consider-
able distance. After passing a vehicle, do not forget the lengt h of
your trailer, and be sure you have plenty of room before changi ng
lanes.
● To maintain engine braking efficiency and charging system perfo r-
mance when using engine braking, do not use the transmission in
D.
Transmission shift ra nge position must be in 4 in the S mode.
● Instability happens more frequently when descending steep or lo ng
downhill grades. Before descending, slow down and downshift. Do
not make sudden downshifts while descending steep or long down-
hill grades.
● Avoid holding the brake pedal down too long or applying the bra kes
too frequently. This could cause the brakes to overheat and result in
reduced braking efficiency.
● Due to the added load of the trailer, your vehicle’s engine may over-
heat on hot days (at temperatures over 85°F [30°C]) when drivin g
up a long or steep grade. If the engine coolant temperature gau ge
indicates overheating, immediately turn off the air conditionin g (if in
use), pull your vehicle off the road and stop in a safe spot.
(  P. 529)

2184-2. Driving procedures
■When the steering lock cannot be released
■ Key reminder function
A buzzer sounds if the driver’s door is opened while the engine switch is in
ACC or OFF to remind you to remove the key. When starting the engine, the engine
switch may seem stuck in the OFF. To
free it, turn the key while turning the steer-
ing wheel slightly left and right.
WARNING
■ When starting the engine
Always start the engine while sitting in the driver’s seat. Do not depress the
accelerator pedal while starting the engine under any circumsta nces.
Doing so may cause an accident resulting in death or serious in jury.
■ Caution while driving
Do not turn the engine switch to OFF while driving. If, in an e mergency, you
must turn the engine off while the vehicle is moving, turn the engine switch
only to ACC to stop the engine. An accident may result if the e ngine is
stopped while driving. ( P. 475)
NOTICE
■To prevent battery discharge
Do not leave the engine switch in ACC or ON for long periods of time with-
out the engine running.
■ When starting the engine
● Do not crank the engine for more than 30 seconds at a time. This may
overheat the starter and wiring system.
● Do not race a cold engine.
● If the engine becomes difficult to start or stalls frequently, have your vehi-
cle checked by your Toyota dealer immediately.