ECU Lexus ES300h 2017 Repair Manual

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ES300h_OM_OM33C75U_(U)7-3. Do-it-yourself maintenance
7
Maintenance and care
12-volt battery
The 12-volt battery is located on the
right-hand side of trunk.
Remove the 12-volt battery cover.
Install the cover
Lift the tab to secure to the trunk
liner
Location
Removing the 12-volt battery cover
Installing the 12-volt battery cover
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ES300h_OM_OM33C75U_(U)7-3. Do-it-yourself maintenance
Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose clamps. Make sure that the terminal cov-
ers are secured over the battery terminals.
Te r m i n a l s
Hold-down clamp
■Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flammable and
explosive. Therefore, observe the following precautions before recharging:
●If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the
ground cable.
●Make sure the power switch on the charger is off when connecting and disconnecting
the charger cables to the 12-volt battery.
■After recharging/reconnecting the 12-volt battery
●The hybrid system may not start. Follow the procedure below to initialize the system.Shift the shift lever to P.
Open and close any of the doors.
Restart the hybrid system.
●Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the 12-volt battery. If this happens, use the
wireless remote control or the mechanical key to lock/unlock the doors.
●Start the hybrid system with the power switch in ACCESSORY mode. The hybrid sys-
tem may not start with the power switch turned off. However, the hybrid system will
operate normally from the second attempt.
●The power switch mode is recorded by the vehicle. If the 12-volt battery is reconnected,
the vehicle will return the power switch mode to the status it was in before the 12-volt bat-
tery was disconnected. Make sure to turn off the power switch before disconnect the 12-
volt battery. Take extra care when connecting the 12-volt battery if the power switch mode
prior to discharge is unknown.
If the system will not start even after multiple attempts at all methods above, contact your
Lexus dealer.
Exterior
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496
ES300h_OM_OM33C75U_(U)7-3. Do-it-yourself maintenance
WA R N I N G
■Replacing light bulbs
●Turn off the lights. Do not attempt to replace the bulb immediately 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 unavoid-
able to hold the glass portion, use and hold with a clean 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 th
e headlight unit. This may damage the head-
lights or cause condensation to build up on the lens.
■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.

5018-2. Steps to take in an emergency
ES300h_OM_OM33C75U_(U)
8
When trouble arises
If your vehicle is transported by a flat
bed truck, it should be tied down at the
locations shown in the illustration.
If you use chains or cables to tie down
your vehicle, the angles shaded in black
must be 45 °.
Do not overly tighten the tie downs or
the vehicle may be damaged.
If a tow truck is not available in an emergency, your vehicle may be temporarily
towed using cables or chains secured to the emergency towing eyelets. This
should only be attempted on hard surf aced roads for short distances at under
18 mph (30 km/h).
A driver must be in the vehicle to steer and operate the brakes. The vehicle’s
wheels, drive train, axles, steering and brakes must be in good condition.
Using a flat bed truck
Emergency towing

5028-2. Steps to take in an emergency
ES300h_OM_OM33C75U_(U)
Take out the towing eyelet. (→P. 5 1 6 )
Remove the eyelet cover using a flat-
head screwdriver.
To protect the bodywork, place a rag
between the screwdriver and the vehi-
cle body as shown in the illustration.
Insert the towing eyelet into the hole
and tighten partially by hand.
Tighten down the towing eyelet
securely using a wheel nut wrench.
Securely attach cables or chains to the towing eyelet.
Take care not to damage the vehicle body.
Enter the vehicle being towed and start the hybrid system.
If the hybrid system does not start, turn the power switch to ON mode.
Shift the shift lever to N and release the parking brake.
When the shift lever cannot be shifted: →P. 1 7 8
Emergency towing procedure
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5038-2. Steps to take in an emergency
ES300h_OM_OM33C75U_(U)
8
When trouble arises
■While towing
If the hybrid system is off, the power assist for the brakes and steering will not function,
making steering and braking more difficult.
■Wheel nut wrench
Wheel nut wrench is installed in trunk. ( →P. 5 1 6 )
WA R N I N G
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When towing the vehicle
■While towing
●When towing using cables or chains, avoid sudden starts, etc. which place excessive
stress on the eyelet, cables or chains. The towing eyelet, cables or chains may
become damaged, broken debris may hit people and cause serious damage.
●Do not turn the power switch off.
There is a possibility that the steering wh eel is locked and cannot be operated.
■Installing towing eyelet to the vehicle
Make sure that towing eyelet is installed securely.
If not securely installed, towing eyelets may come loose during towing.
NOTICE
■To prevent damage to the vehicle when towing using a wheel-lift type truck
●Do not tow the vehicle from the rear when the power 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 oppo-
site end of the raised vehicle. Without adequate clearance, the vehicle could be dam-
aged 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 rear.
■To prevent damage to the vehicle during emergency towing
Do not secure cables or chains to the suspension components.
Be sure to transport the vehicle with the front
wheels raised or with all four wheels raised off
the ground. If the vehicle is towed with the front
wheels contacting the ground, the drivetrain
and related parts may be damaged or electric-
ity generated by the operation of the motor
may cause a fire to occur depending on the
nature of the damage or malfunction.

5078-2. Steps to take in an emergency
ES300h_OM_OM33C75U_(U)
8
When trouble arises
*: Driver’s and front passenger’s seat belt warning buzzer: The driver’s seat belt warning buzzer sounds to alert the driver that his or her seat belt
is not fastened. Once the power switch is turned to ON mode, the buzzer sounds for
6 seconds. If the vehicle reaches a speed of 12 mph (20 km/h), the buzzer sounds
once. If the seat belt is still unfastened after 30 seconds, the buzzer will sound inter-
mittently for 10 seconds. Then, if the seat belt is still unfastened, the buzzer will sound
in a different tone for 20 more seconds.
The front passenger’s seat belt warning buzzer sounds to alert the front passenger
that his or her seat belt is not fastened. The buzzer sounds once if the vehicle reaches
a speed of 12 mph (20 km/h). If the seat be lt is still unfastened after 30 seconds, the
buzzer will sound intermittently for 10 seconds. Then, if the seat belt is still unfastened,
the buzzer will sound in a different tone for 20 more seconds.
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact sensors (front), side impact sensors (rear),
driver’s seat position sensor, driver’s seat belt buckle switch, front passenger occupant
classification system (ECU and sensors), “AIR BAG ON” indicator light, “AIR BAG OFF”
indicator light, front passenger’s seat belt buckle switch, seat belt pretensioner assem-
blies, airbags, inte rconnecting wiring and power sources.
( → P. 3 8 )
Tire pressure warning light
When the light comes on:
Low tire inflation pressure such as
• Natural causes ( →P. 5 0 8 )
•Flat tire ( →P. 5 1 5 )
→ Adjust the tire inflation pressure to the specified level.
The light will turn off after a few minutes. In case the light does
not turn off even if the tire inflation pressure is adjusted, have the
system checked by your Lexus dealer.
When the light comes on after blinking for 1 minute:
Malfunction in the tire pressure warning system ( →P. 5 0 8 )
→ Have the system checked by your Lexus dealer.
(Flashes)
(If equipped)
“A F S O F F ” i n d i c a t o r
Indicates a malfunction in the adaptive front-lighting system
→ Have the vehicle inspected by your Lexus dealer immediately.
Warning lightWarning light/Details/Actions

5088-2. Steps to take in an emergency
ES300h_OM_OM33C75U_(U)
■Front passenger detection sensor, seat belt reminder and warning buzzer
●If luggage is placed on the front passenger seat, the front passenger detection sensor
may cause the warning light to flash and the warning buzzer to sound even if a passen-
ger is not sitting in the seat.
●If a cushion is placed on the seat, the sensor may not detect a passenger, and the warn-
ing light may not operate properly.
■Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insufficient or the voltage temporarily drops,
the electric power steering system warnin g light may come on and the warning buzzer
may sound.
■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 Lexus dealer as soon as
possible.
■When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Pushing the tire
pressure warning reset switch will not turn off the tire pressure warning light.
■The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such as natural air
leaks and tire inflation pressure changes caused by temperature. In this case, adjusting
the tire inflation pressure will turn off the warning light (after a few minutes).
■When a tire is replaced with a spare tire
The compact spare tire is not equipped with a tire pressure warning valve and transmit-
ter. If a tire goes flat, the tire pressure warning light will not turn off even though the flat
tire has been replaced with the spare tire.
■Conditions that the tire pressure warning system may not function properly
→ P. 4 6 9
■If the tire pressure warning light freque ntly comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute when the
power switch is turned to ON mode, ha ve it checked by your Lexus dealer.
■Warning buzzer
In some cases, the buzzer may not be heard because of noisy place or an audio sound.

5188-2. Steps to take in an emergency
ES300h_OM_OM33C75U_(U)
Open the luggage mat. (→P. 4 0 8 )
Remove the auxiliary boxes.
Loosen the center fastener that
secures the spare tire.
Taking out the spare tire
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WA R N I N G
■When storing the spare tire
Be careful not to catch fingers or other body parts between the spare tire and the body
of the vehicle.

5248-2. Steps to take in an emergency
ES300h_OM_OM33C75U_(U)
WA R N I N G
■When using the compact spare tire
●Remember that the compact spare tire provided is specifically designed for use with
your vehicle. Do not use your compact spare tire on another vehicle.
●Do not use more than one compact spare tire simultaneously.
●Replace the compact spare tire with a standard tire as soon as possible.
●Avoid sudden acceleration, abrupt steering, sudden braking and shifting operations
that cause sudden engine braking.
■When the compact spare tire is attached
The vehicle speed may not be correctly detected, and the following systems may not
operate correctly:
■Speed limit when using the compact spare tire
Do not drive at speeds in excess of 50 mph (80 km/h) when a compact spare tire is
installed on the vehicle.
The compact spare tire is not designed for driving at high speeds. Failure to observe
this precaution may lead to an accident causing death or serious injury.
■After using the tools and jack
Before driving, make sure all the tools and jack are securely in place in their storage
location to reduce the possibility of personal injury during a collision or sudden brak-
ing.
NOTICE
■Driving with tire chains and the compact spare tire
Do not fit tire chains to the compact spare tire.
Tire chains may damage the vehicle body and adversely affect driving performance.
■When replacing the tires
When removing or fitting the wheels, tires or the tire pressure warning valve and trans-
mitter, contact your Lexus dealer as the tire pressure warning valve and transmitter
may be damaged if not handled correctly.
• ABS & Brake assist
•VSC
•TRAC
•Cruise control
• Dynamic radar cruise control (if equipped)
•PCS (if equipped) •EPS
• LDA (Lane Departure Alert with
steering control) (if equipped)
• Lexus parking assist monitor
• Intuitive parking assist (if equipped)
• Navigation system (if equipped)