2021 TOYOTA 4RUNNER engine overheat

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4RUNNER (U)6-1. Maintenance and care
Cleaning and protecting the vehicle exterior .......... 392
Cleaning and protecting the vehicle interior ........... 395
6-2. Maintenance Maintenance requirements ................... 398
General maintenance ........ 400
Emission inspection and maintenance (I/M)
programs ......................... 403
6-3. Do-it-yourself maintenance
Do-it-yourself service precautions ..................... 404
Hood.................................. 407
Engine compartment ......... 408
Tires .................................. 422
Tire inflation pressure........ 436
Wheels .............................. 439
Air conditioning filter .......... 441
Wireless remote control/ electronic key
battery ............................. 443
Checking and replacing fuses ............................... 446
Light bulbs ......................... 449 7-1. Essential information
Emergency flashers ........... 462
If your vehicle has to be stopped in an
emergency....................... 463
If the vehicle is trapped in rising water ...................... 465
7-2. Steps to take in an emergency
If your vehicle needs to be towed .......................... 466
If you think something is wrong............................... 472
Fuel pump shut off system ............................. 473
If a warning light turns on or a warning buzzer
sounds ............................. 474
If a warning message is displayed ......................... 484
If you have a flat tire .......... 489
If the engine will not start ................................. 504
If you cannot operate back door opener ............ 506
If the electronic key does not operate properly
(vehicles with a smart
key system) ..................... 507
If the vehicle battery is discharged ....................... 510
If your vehicle overheats......................... 514
If the vehicle becomes stuck ................................ 517
6Maintenance and care7When trouble arises

15Pictorial index
4RUNNER (U)
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 422
Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . P. 528
Winter tires/tire chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 329
Checking/rotation/tire pressur e warning system . . . . . . . . .P. 422
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 489
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 407
Opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 407
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 523
Coping with overheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 514
Headlights/daytime running lights . . . . . . . . . . . . . . . . . . . . P. 225
Front side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 225
Front turn signal/parking lights . . . . . . . . . . . . . . . . . . . . . . P. 225
Fog lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 234
Turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 223
Stop/tail lights/rear side marker lights . . . . . . . . . . . . . . . . P. 225
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 225
Back-up lights
Shifting the shift lever to R . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 218
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Light bulbs of the exterior lights for driving
(Replacing method: P. 449, Wattages: P. 529)
*: Vehicles with a smart key system
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892. Instrument cluster
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Instrument cluster
4RUNNER (U)
Switches between odometer and
trip meter displays. When the trip
meter is displayed, pressing and
holding the button will reset the
trip meter.
The brightness of the instrumen t panel lights can be adjusted.
Brighter
Darker
■ The meters and display illuminate when
Vehicles without a smart key system
The engine switch is in the “ON” position.
Vehicles with a smart key system
The engine switch is in IGNITION ON mode.
■ The brightness of the instrument panel lights
When the headlight switch is turned to on, the brightness will be reduced
slightly unless the control dial is turned fully upward.
Changing the display
Instrument panel light control
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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. 514)

1794-1. Before driving
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Driving
4RUNNER (U)
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■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 ac cident.
• When backing up, you may twist your body around, leading to a diffi-
culty in operating the pedals. Make sure to operate the pedals properly.
• 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.
■ When driving the vehicle
● 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. 463
● 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. 218)
● 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.
● Do not drive in excess of the speed limit. Even if the legal sp eed limit per-
mits it, do not drive over 85 mph (140 km/h) unless your vehicl e has high-
speed capability tires. Driving over 85 mph (140 km/h) may resu lt in tire
failure, loss of control and possible injury. Be sure to consult a tire dealer
to determine whether the tires on your vehicle are high-speed c apability
tires or not before driving at such speeds.

1814-1. Before driving
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Driving
4RUNNER (U)
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■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 needed.
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 accelerate
suddenly 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.

1834-1. Before driving
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Driving
4RUNNER (U)
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■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.
● 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.
If this happens, do not continue to drive the vehicle. Have you r brakes
fixed immediately.

2024-1. Before driving
4RUNNER (U)
●Avoid jerky starts or sudden acceleration.
● Avoid jerky steering and sharp turns, and slow down before maki ng
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 cross winds, on wet or slipp ery
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 put the transmission in
D.
● 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. 514)

2114-2. Driving procedures
4
Driving
4RUNNER (U)
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 when driving
Do not turn the engine switch to the “LOCK” position while driving. If, in an
emergency, you must turn the engine off while the vehicle is mo ving, turn
the engine switch only to the “ACC” position to stop the engine. An accident
may result if the engine is stopped while driving.
NOTICE
■ To prevent battery discharge
Do not leave the engine switch in the “ACC” or “ON” position fo r long peri-
ods of time without 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 systems.
● Do not race a cold engine.
● If the engine becomes difficult to start or stalls frequently, have the engine
checked immediately.