Page 221 of 608

221
2-4. Using other driving systems
2
When driving
●The vehicle speed deviates from the operating range of the LKA system func-
tions.
●When the lane lines cannot be recognized while driving.
●Low speed or high speed wiper operation states.  
The buzzer may not beep when the LKA system functions are canceled 
because the notification of dynamic radar cruise control cancellation takes pri-
ority over the LKA system and cancels the function.
●The no-handed driving warning activates while the lane keeping assist function 
is active. (The buzzer will beep twice.)
■No-handed driving warning
If the steering wheel is not operated for  about 15 seconds on a straight road or 
about 5 seconds on a curve, the buzzer will beep twice, indicators on the multi-
information display will flash, and the lane keeping assist function will be temporarily 
canceled. If you drive the vehicle with your hands lightly touching the steering 
wheel, this may also be detected as no-handed driving.
■When the vehicle has been parked in the sun
The LKA system functions may not be available for a while after driving has started. 
In such cases, turn the LKA system off and turn it on again after normal temperature 
returns. When the temperature in the cab in decreases and the temperature around 
the camera sensor becomes suitable for it s operation, the functions will begin to 
operate.
■Warning lights and messages for LKA
Warning lights and messages ar e used to indicate a system malfunction or to inform 
the driver of the need for caution while driving. ( P. 493, 505) 
     
        
        Page 459 of 608

459
4-3. Do-it-yourself maintenance
4
Maintenance and care
10AM27. 5  A
Smart access system with push-button 
start, hybrid system, multiport fuel 
injection system/sequential multiport 
fuel injection system, P position con-
trol system, cruise control system, 
dynamic radar cruise control system
11ECU-B27. 5  A
Smart access system with push-button 
start, multiport fuel injection system/
sequential multiport fuel injection sys-
tem, trunk opener switch
12MAYDAY10 ALexus link system
13ECU-B310 AAir conditioning system, rear window 
defogger, mirror heater
14TURN & HAZ10 ATurn signal lights, emergency flashers
15ETCS10 A
Multiport fuel injection system/
sequential multiport fuel injection sys-
tem
16ABS MAIN NO.120 AElectronically controlled brake system
17P/I 240 A
P position control system, hybrid sys-
tem, transmission, smart access sys-
tem with push-button start, horn, 
headlights (low beam), back-up lights
18ABS MTR 130 AElectronically controlled brake system
19ABS MTR 230 AElectronically controlled brake system
20H-LP HI MAIN20 AHeadlights (high beam)
21AMP NO.230 AAudio system, navigation system
22DOOR NO.225 ANo circuit
FuseAmpereCircuit 
     
        
        Page 463 of 608
463
4-3. Do-it-yourself maintenance
4
Maintenance and care
3IGN10 A
Electronically controlled brake sys-
tem, multiport fuel injection system/
sequential multiport fuel injection sys-
tem, Lexus link system, smart access 
system with push-button start, stop 
lights
4MET7. 5  AMeters
5WIP30 AWindshield wipers
6WA S H E R15 AWindshield washer
7A/C10 AAir conditioning system
8GAUGE10 AAFS, turn signal lights, emergency 
flasher lights
9AFS10 AAdaptive front-lighting system
10ECU-IG NO.210 A
Pre-collision system, LKA, dynamic 
radar cruise control, air conditioning 
system, outside rear view mirror, 
HUD, navigation system, tire inflation 
pressure warning system
FuseAmpereCircuit 
     
        
        Page 494 of 608
494
5-2. Steps to take in an emergency
Electric power steering system warning light (warning 
buzzer)Indicates a malfunction in the EPS (Electric Power Steering) 
system
(Flashing)
“PCS” warning light (if equipped)Indicates a malfunction in the pre-collision system 
 P.  2 3 2
(Flashing)
“AFS OFF” indicator light (if equipped)
Indicates a malfunction in the AFS (Adaptive Front-lighting 
System)
Slip indicator light
Indicates a malfunction in:
• Enhanced VSC system;
•TRAC system; or
• Hill-start assist control system
(Flashing)
“LKA” indicator light (if equipped)Indicates a malfunction in the lane keeping assist system 
 P.  2 1 7
(Flashing)
Cruise control indicator light
Indicates a malfunction in the cruise control system
  P.  2 0 1 205
(Flashing)
Radar cruise control indicator light (if equipped)
Indicates a malfunction in the Dynamic radar cruise control 
system  P.  2 0 5
Warning lightWarning light/Details 
     
        
        Page 503 of 608
5
When trouble arises
503
5-2. Steps to take in an emergency
(If equipped)
Indicates a malfunction in the intuitive parking assistA buzzer also sounds.
The malfunctioning assi st-sensor is flashing.
 (Flashes)
Indicates a malfunction in the cruise control system
A buzzer also sounds.
Press the “ON-OFF” button once to deactivate the 
system, and then press the button again to reactivate 
the system.
 (Flashes)
(If equipped)
Indicates a malfunction in the radar cruise control 
system A buzzer also sounds.
Stop the vehicle in a safe place. Turn the “POWER” 
switch off and then turn it to ON mode again to reset 
the cruise control system.
Indicates a malfunction in the EPS (Electric Power 
Steering) systemA buzzer also sounds.
If the steering wheel becomes heavier than usual 
when operating, hold firm ly and operate using more 
force than usual.
Wa r n i n g  m e s s a g eDetails 
     
        
        Page 508 of 608
508
5-2. Steps to take in an emergency
(Flashes)
(If equipped)
Indicates that the radar 
cruise control sensor is 
dirty or covered with ice A buzzer also sounds.
Clean the sensor.
(Flashes)
(If equipped)
Indicates that the radar 
cruise control system is 
unable to judge vehicle-
to-vehicle distance A buzzer also sounds.• Switch driving mode to normal.
•Stop the wiper or  change the mode to 
auto, low or intermittent.
(Flashes)
(If equipped)
Alerts the driver that 
there is a high possibility 
of collision or the pre-col-
lision brake has activated A buzzer also sounds.
At the same time, 
 will appear on 
the head-up display too 
(the image flashes).
Slow the vehicle by apply-
ing the brakes.
Wa r n i n g  m e s s a g eDetailsCorrection procedure 
     
        
        Page 520 of 608
520
5-2. Steps to take in an emergency
■Warning light display in radar cruise mode
In the following cases, the warning light may
  not be displayed even if vehicle-to-
vehicle distance decreases:
●When your vehicle and the vehicle ahead are traveling at the same speed or the 
vehicle ahead is traveling more quickly than your vehicle
●When the vehicle ahead is traveling at a very low speed
●Immediately after cruise control speed is set
●At the instant the accelerator pedal is depressed
■After changing the engine oil (U.S.A. only)
Make sure to reset the oil maintenance data. ( P.
  4 2 6 ) 
     
        
        Page 527 of 608

5
When trouble arises
527
5-2. Steps to take in an emergency
CAUTION
■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, deceleration an d braking, as well as sharp cornering.
■When storing the compact spare tire
Be careful not to catch fingers or other body parts between the compact spare tire 
and the body of the vehicle.
■When the compact spare tire is attached
The vehicle speed may not be correctly detected, and the following systems may 
not operate correctly:
●ABS & Brake assist
●Enhanced VSC
●TRAC
●Cruise control system
●Dynamic radar cruise control system (if equipped)
●Lane keeping assist (if equipped)
●Adaptive Front-lighting System (if equipped)
●Intuitive parking assist (if equipped)
●Pre-collision system (if equipped)
●Navigation system (if equipped)
■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.