2019 LEXUS RX450H Owners Manual

2254-1. Before driving
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Driving
RX450h_RX450hL_U
■GCWR (Gross Combination Weight Rating)
The maximum allowable gross com-
bination weight. The gross combina-
tion weight is the sum of the total
vehicle weight (including the occu-
pants, cargo and any optional equip-
ment installed on the vehicle) and
the weight of the trailer being towed
(including the cargo in the trailer).
■GVWR (Gross Vehicle Weight Rating)
The maximum allowable gross vehi-
cle weight. The gross vehicle weight
is the total weight of the vehicle.
When towing a trailer, it is the sum of
the vehicle weight (including the
occupants, cargo and any optional
equipment installed on the vehicle)
and the tongue weight.
■GAWR (Gross Axle Weight Rating)
The maximum allowable gross axle
weight. The gross axle weight is the
load placed on each axle (front and
rear).
Towing related terms
Front GAWR
Rear GAWR

2264-1. Before driving
RX450h_RX450hL_U
■TWR (Trailer Weight Rating)
The maximum allowable gross trailer
weight. The gross trailer weight is
the sum of the trailer weight and the
weight of the cargo in the trailer.
TWR is calculated assuming base
vehicle with one driver, one front
passenger, towing package (if avail-
able), hitch and hitch systems (if
required).
Additional optional equipment, passengers and cargo in the vehicle will reduce the
trailer weight rating so as not to exceed GCWR, GVWR and GAWR.
If the gross trailer weight exceeds 3000 lb. (1360 kg), it is recommended to use a
trailer with 2 or more axles.
■Unbraked TWR (Unbraked Trailer Weight Rating)
The trailer weight rating for towing a
trailer without a trailer service brake
system.
■Tongue Weight
The load placed on the trailer hitch
ball. ( P. 228)
(With brakes)
(Without brakes)

2274-1. Before driving
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Driving
RX450h_RX450hL_U
●The gross trailer weight must never exceed 3500 lb. (1585 kg).
●The gross combination weight must never exceed 9500 lb. (4309 kg).
●The gross vehicle weight must never
exceed the GVWR indicated on the
Certification Label.
●The gross axle weight on each axle
must never exceed the GAWR indi-
cated on the Certification Label.
●If the gross trailer weight is over the unbraked TWR, trailer service brakes are
required.
●If the gross trailer weight is over 2000 lb. (907 kg), a sway control device with
sufficient capacity is required.
Confirm that the gross trailer weight, gross combination weight, gross vehicle
weight, gross axle weight and tongue weight are all within the limits.
■GCWR*
9500 lb. (4309 kg)
■TWR*
3500 lb. (1585 kg)
■Unbraked TWR*
1000 lb. (453 kg)
*: These models meet the tow-vehicle trailering requirement of SAE International per
SAE J2807.
Weight limits
GCWR, TWR and Unbraked TWR

2284-1. Before driving
RX450h_RX450hL_U
●A recommended tongue weight varies in accordance with the types of trailers
or towing as described below.
●To ensure the recommended values show n below, the trailer must be loaded
by referring to the following instructions. • Tongue Weight
The gross trailer weight should be dist ributed so that the tongue weight is
9% to 11%.
(Tongue weight/Gross trailer weight x 100 = 9% to 11%)
Gross trailer weight
Tongue weight
The gross trailer weight, gross axle weight and tongue weight can be mea-
sured with platform scales found at a highway weighing station, building
supply company, trucking company, junk yard, etc.
Trailer hitch assemblies have different weight capacities. Lexus recommends the
use of Lexus hitch/bracket for your ve hicle. For details, contact your Lexus
dealer.
●If you wish to install a trailer hitch, contact your Lexus dealer.
●Use only a hitch that conforms to the gross trailer weight requirement of your
vehicle.
●Follow the directions supplied by the hitch manufacturer.
●Lubricate the hitch ball with a light coating of grease.
●Remove the trailer hitch whenever you ar e not towing a trailer. After removing
the hitch, seal any mounting hole in the vehicle body to prevent entry of any
substances into the vehicle.
Trailer Tongue Weight
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Hitch

2294-1. Before driving
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Driving
RX450h_RX450hL_U
Use the correct trailer ball for your application.Trailer ball load rating
Matches or exceeds the gross trailer
weight rating of the trailer.
Ball diameter
Matches the size of the trailer coupler.
Most couplers are stamped with the
required trailer ball size.
Shank length
Protrudes beyond the bottom of the lock washer and nut by at least 2 threads.
Shank diameter
Matches the ball mount hole diameter size.
Weight carrying ball position:
44.96 in. (1142 mm)
Hitch receiver pin hole position:
35.94 in. (913 mm)
Selecting trailer ball
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Trailer classTypical trailer ball size
IV2 5/16 in.
II and III2 in.
I1 7/8 in.
Positions for towing hitch receiver and hitch ball
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4
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2

2304-1. Before driving
RX450h_RX450hL_U
Use the wire harness stored in the rear
end under body.
■Auto current cut-off function
In case of over current, the auto cut-off function stops the power flowing to the trailer
lights to prevent damage to the vehicle’s electrical system.
This function is activated when the rated current of any of the following trailer light circuit
components is exceeded:
●Tail lights: maximum 7.8 A
●Stop/turn signal light (right): maximum 4.5 A
●Stop/turn signal light (left): maximum 4.5 A
■When the auto current cu t function is activated
If a trailer light does not come on due to th e activation of the auto current cut function,
the light system will need to be reset.
Follow the reset procedure shown below.
●If a tail light does not come on, turn off the headlight switch.
●If the right-side stop/turn signal light does not come on, put the turn signal in the off
position or remove foot from the brake pedal.
●If the left-side stop/turn signal light does not come on, put the turn signal in the off posi-
tion or remove foot from the brake pedal.
If the emergency flashers do not operate, press the emergency flasher switch to turn
them off.
After the light system is reset, operate the lig ht switches again to see if the lights operate
normally.
If the lights do not operate normally, have the vehicle inspected by your Lexus dealer.
Connecting trailer lights

2314-1. Before driving
4
Driving
RX450h_RX450hL_U
Your vehicle will handle differently when towing a trailer. Help to avoid an acci-
dent, death or serious injury, keep the following in mind when towing:
●Speed limits for towing a trailer vary by state or province. Do not exceed the
posted towing speed limit.
●Lexus recommends that the vehicle-traile r speed limit is 65 mph (104 km/h)
on a flat, straight, dry road. Do not exce ed this limit, the posted towing speed
limit or the speed limit for your trailer as set forth in your trailer owner’s man-
ual, whichever is lowest. Instability of the towing vehicle-trailer combination
(trailer sway) increases as speed increases. Exceeding speed limits may cause
loss of control.
●Before starting out, check the trailer lights, tires and the vehicle-trailer con-
nections. Recheck after driving a short distance.
●Practice turning, stopping and reversing with the trailer attached in an area
away from traffic until you become acc ustomed to the feel of the vehicle-
trailer combination.
●Reversing with a trailer attached is di fficult and requires practice. Grip the
bottom of the steering wheel and move your hand to the left to move the
trailer to the left. Move your hand to the right to move the trailer to right. (This
is generally opposite to reversing with out a trailer attached.) Avoid sharp or
prolonged turning. Have someone guid e you when reversing to reduce the
risk of an accident.
●As stopping distance is increased when towing a trailer, vehicle-to vehicle dis-
tance should be increased. For each 10 mph (16 km/h) of speed, allow at least
one vehicle and trailer length.
●Avoid sudden braking as you may skid, resulting in the trailer jackknifing and a
loss of vehicle control. This is especi ally true on wet or slippery surfaces.
●Avoid jerky starts or sudden acceleration.
●Avoid jerky steering and sharp turns, an d slow down before making 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 making a wider than normal
turning radius.
●Slow down before making a turn, in cross winds, on wet or slippery surfaces,
etc.
Increasing vehicle speed can destabilize the trailer.
●Take care when passing other vehicles . Passing requires considerable dis-
tance. After passing a vehicle, do not fo rget the length of your trailer, and be
sure you have plenty of room before changing lanes.
Trailer towing tips

2324-1. Before driving
RX450h_RX450hL_U
●To maintain engine braking efficien cy and charging system performance
when using engine braking, do no t put the transmission in D. (P. 246)
●Instability happens more fr equently when descending steep or long downhill
grades. Before descending, slow down and downshift. Do not make sudden
downshifts while descending st eep or long downhill grades.
●Avoid holding the brake pedal down too long or applying the brakes too fre-
quently. This could cause the brakes to overheat and result in reduced braking
efficiency.
●Due to the added load of the trailer, yo ur vehicle’s engine may overheat on hot
days (at temperatures over 85 F [30 C]) when driving up a long or steep
grade. If the engine coolant temperat ure gauge indicates overheating, imme-
diately turn off the air conditioning (if in use), pull your vehicle off the road and
stop in a safe spot. ( P. 702)
●Always place wheel blocks under both the vehicle’s and the trailer’s wheels
when parking. Put the transmission in P and apply the parking brake. Avoid
parking on a slope, but if unavoidable, do so only after performing the follow-
ing:
Apply the brakes and keep them applied.
Have someone place wheel blocks under both the vehicle’s and trailer’s
wheels.
When the wheel blocks are in place, release the brakes slowly until the
blocks absorb the load.
Shift into P and apply the parking brake.
Turn off the hybrid system.
●When restarting afte r parking on a slope:
With the transmission in P, start the hybrid system. Be sure to keep the
brake pedal depressed.
Shift into a forward gear. If reversing, shift into R.
If the parking brake is in manual mode, release the parking brake.
( P. 254)
Release the brake pedal, and slowly pull or back away from the wheel
blocks. Stop and apply the brakes.
Have someone retrieve the blocks.
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