2021 TOYOTA TUNDRA vehicle battery is discharged

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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

1413-2. Opening, closing and locking the doors
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Operation of each component
■Battery-saving function
The battery-saving function will be activated in order to preve nt the electronic
key battery and the battery from being discharged while the veh icle is not in
operation for a long time.
● In the following situations, the smart key system may take some time to
unlock the doors.
• The electronic key has been left in an area of approximately 6 ft. (2 m) of
the outside of the vehicle for 10 minutes or longer.
• The smart key system has not been used for 5 days or longer.
● If the smart key system has not been used for 14 days or longer , the doors
cannot be unlocked at any door except the driver’s door. In thi s case, take
hold of the driver’s door handle, or use the wireless remote co ntrol or the
mechanical key, to unlock the doors.
The system will resume operation when
● The vehicle is locked using the door handle lock switch when ca rrying the
electronic key on your person.
● The vehicle is locked/unlocked using the wireless remote contro l. (P. 128)
● The vehicle is locked/unlocked using the mechanical key. ( P. 523)
■ Electronic Key Battery-Saving Function
When battery-saving mode is set, battery depletion is minimized by stopping
the electronic key from receiving radio waves.
Press twice while pressing and
holding . Confirm that the electronic
key indicator flashes 4 times.
While the battery-saving mode is set, the
smart key system cannot be used. To
cancel the function, press any of the elec-
tronic key buttons.

4116-2. Maintenance
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Maintenance and care
Emission inspection and maintenance (I/M)
programs
The OBD system determines that a problem exists somewhere in th e
emission control system. Your vehicle may not pass the I/M test and
may need to be repaired. Contact your Toyota dealer to service the
vehicle.
● When the battery is disc onnected or discharged
Readiness codes that are set duri ng ordinary driving are erased.
Also, depending on your driving habits, the readiness codes may
not be completely set.
● When the fuel tan k cap is loose
The malfunction indicator lamp comes on indicating a temporary
malfunction and your vehicle m ay not pass the I/M test.
The error code in th e OBD system will not be cleared unless the vehi-
cle is driven 40 or more times.
Contact your Toyota dea ler to prepare the vehicle for re-testin g.
Some states have vehicle emission inspection programs which
include OBD (On Board Diagnostics) checks. The OBD system
monitors the operation of t he emission control system.
If the malfunction indicator lamp comes on
Your vehicle may not pass the I/M test in the following situations:
When the malfunction indicator lamp still remains on after sev-
eral driving trips
If your vehicle does not pass the I/M test

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7When trouble arises
7-1. Essential informationEmergency 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

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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 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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