2021 TOYOTA TUNDRA ECU

4726-3. Do-it-yourself maintenance
WARNING
■Replacing light bulbs
● Turn off the lights. Do not attempt to replace the bulb immedia tely after
turning off the lights.
The bulbs become very hot and may cause burns.
● Do not touch the glass portion of the light bulb with bare hands. When it is
unavoidable to hold the glass portion, use and hold with a clea n dry cloth
to avoid getting moisture and oils on the bulb.
Also, if the bulb is scratched or dropped, it may blow out or crack.
● Fully install light bulbs and any parts used to secure them. Failure to do so
may result in heat damage, fire, or water entering the headligh t unit. This
may damage the lights or cause condensation to build up on the lens.
● Do not attempt to repair or disassemble the bulb, bulb base, el ectrical wir-
ing, or subcomponents.
Doing so could result in electric shock and serious injury.
■ To prevent damage or fire
● Make sure bulbs are fully seated and locked.
● Check the wattage of the bulb before installing to prevent heat damage.

475
7
When trouble arises
7-1. Essential information
If your vehicle has to be stopped in an
emergency
Steadily step on the brake pedal with both feet and firmly depress it.
Do not pump the brake pedal repeatedly as this will increase th e effort
required to slow the vehicle.
Shift the shift lever to N.
If the shift lever is shifted to N
After slowing down, stop the vehi cle in a safe place by the road.
Stop the engine.
If the shift lever cann ot be shifted to N
Keep depressing the brake pedal with both feet to reduce vehicl e
speed as much as possible.
Vehicles without a smart key
system: Stop the engine by
turning the engine switch to
ACC.
Vehicles with a smart key sys-
tem: To stop the engine, press
and hold the engine switch for 2
consecutive seconds or more,
or press it briefly 3 times or
more in succession.
Stop the vehicle in a s afe place by the road.
Only in an emergency, such as if it becomes impossible to stop
the vehicle in the normal way, st op the vehicle using the follow-
ing procedure:
1
2
3
4
3
4
Press and hold for 2 seconds or more
or press briefly 3 times or more
Q
R

4797-2. Steps to take in an emergency
7
When trouble arises
WARNING
■While towing
● When towing using cables or chains, avoid sudden starts, etc. w hich place
excessive stress on the towing eyelets, cables or chains. The towing eye-
lets, cables or chains may become damaged, broken debris may hit peo-
ple, and cause serious damage.
● Do not turn the engine switch to OFF.
There is a possibility that the steering wheel is locked and ca nnot be oper-
ated.
NOTICE
■ To prevent damage to the vehicle when towing using a wheel-lift type
truck
● Vehicles without a smart key system:
Do not tow the vehicle from the rear when the engine switch is in OFF or
the key is removed.
The steering lock mechanism is not strong enough to hold the front wheels
straight.
● Vehicles with a smart key system:
Do not tow the vehicle from the rear when the engine switch is off.
The steering lock mechanism is not strong enough to hold the front wheels
straight.
● When raising the vehicle, ensure adequate ground clearance for towing at
the opposite end of the raised vehicle. Without adequate clearance, the
vehicle could be damaged while being towed.
■ To prevent damage to the vehicle when towing with a sling-type truck
Do not tow with a sling-type truck, either from the front or re ar.
■ To prevent damage to the vehic le during emergency towing
Do not secure cables or chains to the suspension components.

4817-2. Steps to take in an emergency
7
When trouble arises
When using a flat-bed truck to transport the vehicle, use tire strapping
belts. Refer to the owner’s manual of the flat-bed truck for th e tire
strapping method.
In order to suppress vehicle movement during transportation, se t the
parking brake and turn th e engine switch to OFF.
If a tow truck is not available in an emergency, your vehicle m ay be
temporarily towed using cables or chains secured to the emergen cy
towing hooks. This should only be attempted on hard surfaced roads
for at most 50 miles (80 km) at under 18 mph (30km/h).
A driver must be in the vehicle to steer and operate the brakes . The
vehicle’s wheels, drive train, a xles, steering and brakes must be in
good condition.
NOTICE
■ Towing with a sling-type truck
Using a flatbed truck
Emergency towing
Do not tow with a sling-type truck to pre-
vent body damage.

4827-2. Steps to take in an emergency
Securely attach cables or chains to the towing hooks.
Take care not to damage the vehicle body.
Enter the vehicle being towed and start the engine.
If the engine does not start, turn the engine switch to ON.
4WD models: Put the front-wheel drive control switch in “2WD”.
Shift the shift lever to N and release the parking brake.
When the shift lever cannot be shifted. (P. 229)
■While towing
If the engine is not running, the power assist for the brakes a nd steering will
not function, marking steering and braking more difficult.
Emergency towing procedure
1
Ty p e AType B
2
3
4

4897-2. Steps to take in an emergency
7
When trouble arises
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact
sensors, side impact sensors (front door), side impact sensors (rear), driver’s
seat position sensor, driver’s seat belt buckle switch, front passenger occu-
pant classification system (ECU and sensors), “AIR BAG ON” indi cator light,
“AIR BAG OFF” indicator light, front passenger’s seat belt buck le switch, seat
belt pretensioners assemblies, airbags, interconnecting wiring and power
sources. ( P. 42)
■ Front passenger detection sensor, seat belt reminder and warnin g
buzzer
● If luggage is placed on the front passenger seat, the front pas senger detec-
tion sensor may cause the warning light to flash and the warnin g buzzer to
sound even if a passenger is not sitting in the seat.
● If a cushion is placed on the seat, the sensor may not detect a passenger,
and the warning light may not operate properly.
■ If the malfunction indicator lamp comes on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fuel tank immediately.
● Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving trips.
If the light does not go off even after several trips, contact your Toyota dealer
as soon as possible.
■
When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Push-
ing the tire pressur e warning reset switch will not turn off the tire pressure
warning light.

5007-2. Steps to take in an emergency
(If equipped)
Indicates that, since the VSC (Vehicle Stability
Control) system was turned off, the pre-collision
brake system operation is stopped.
Turn the VSC on. ( P. 323)
(If equipped)
Indicates that the pre-collision system is tempo-
rarily unavailable.
Please wait until the system returns. If the
message does not disappear, the system
may be malfunctioning. Have the vehicle
inspected by your Toyota dealer immedi-
ately.
(If equipped)
Indicates that the pre-collision system sensor is
dirty, covered with ice, etc.
Remove any dirt, ice, etc.
Indicates a malfunction in the RCTA (Rear Cross
Traffic Alert).
A buzzer also sounds.
 Have the vehicle inspected by your Toyota
dealer.
Indicates that the VSC ECU or G sensor is not
communicating with trailer brake control system.
Indicates a malfunction in the VSC system.
Have the vehicle inspected by your Toyota
dealer immediately.
Warning messageDetails/Actions
VSC Turned Off
Pre-Collision Brake
System
Unavailable
Pre-Collision System Unavailable
Pre-Collision System Unavailable
Clean Sensor
Rear Cross Traffic Alert Malfunction
Visit Your Dealer
Trailer Brake Error. If Towing,
Come to a Safe Stop
with Manual Controls.
Contact dealer.

5047-2. Steps to take in an emergency
Once
The steering lock could not be
released within 3 seconds of
the engine switch being
pressed.
Press the engine switch
while depressing the
brake pedal and moving
the steering wheel left
and right.
Once
• When the doors were
unlocked with the mechani-
cal key and then the engine
switch was pressed, the
electronic key could not be
detected in the vehicle.
• The electronic key could not be detected in the vehicle
even after the engine switch
was pressed two consecu-
tive times.
 Touch the electronic key
to the engine switch
while depressing the
brake pedal.
Once
Indicates that:
• With the engine switch off,
the doors were unlocked
and then the driver’s door
was opened and closed
• The engine switch was turned to ACC without start-
ing the engine
 Press the engine switch
while depressing the
brake pedal.
Once
The engine switch has been
turned off with the shift lever in
a position other than P.
Shift the shift lever to P.
Interior
buzzerExterior buzzerWarning messageDetails/Actions
Steering Lock ON
(Flashes)
Engine Start:
Press Brake Pedal,
Touch Engine Switch
with Key
Engine Start:
Press Brake Pedal and
Push Engine Switch
Shift into P Position
(Flashes)