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103
2-1. Driving procedures
2
When driving
■Downshifting restrictions in “S” mode
The shift lever cannot be downshifted if the following speeds are exceeded. (The 
w
arning buzzer will sound twice in this situation.)
The maximum speeds can get lower when the  engine is not warm such as in cold 
climates or before warm-up.
■When driving with the cruise control syst em (or dynamic radar cruise control sys-
tem)
The engine brake will not operate in the “S”  mode, e
 ven when downshifting to “5” or 
“4”. ( P.  1 2 4 , 127 )
■Snow mode automatic deactivation
Snow mode is automatically deactivated if  the e
 ngine switch is turned to “ACC” or 
“IG-ON” mode after driving in snow mode. 
■If the shift lever cannot be shifted from “P”
 P.
 4 8 4
■If the   indicator does not come on even after shifting the shift lever to “S”
This may indicate a malfunction in the automatic transmission system. Have the 
v
 ehicle inspected by your Lexus dealer immediately.  
(In this situation, the vehicle will operate as if the shift lever is in “D”.)
■AI-SHIFT
The AI-SHIFT automatically shifts the gear  to
  the optimal position according to the 
driver's input and driving conditions. 
The AI-SHIFT automatically operates when th e
  shift lever is in the D position. (Shift-
ing the shift lever to the S position cancels the function.)
Downshifting
Maximum speed 
mph (km/h)
GS430GS350
5 4120 (194)124 (200)
4 388 (142)87 (141)
3 259 (95)56 (91)
2 124 (38)28 (45) 
     
        
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366
4-2. Maintenance
Vehicle interior
ItemsCheck points
Accelerator pedal• Moves smoothly (without uneven pedal effort or catching)?
Automatic transmission 
“Park” mechanism• Can the vehicle be hold securely on an incline with the shift lever in “P”?
Brake pedal
• Moves smoothly?
• Does it have appropriate clearance and correct amount of free play?
Brakes
• Pulls to one side when applied?
• Loss of brake effectiveness?
• Spongy feeling brake pedal?
• Pedal almost touches floor?
Head restraints• Move smoothly and lock securely?
Indicators/buzzers• Function properly?
Lights• Do all the lights come on?
• Headlights aimed correctly? ( P.  4 2 9 )
Pa r k i n g  b r a ke
• Moves smoothly?
• Can hold the vehicle securely on an 
incline?
Seat belts
• Does the seat belt system operate smoothly?
• Are the belts undamaged?
Seats• Do the seat controls operate properly?
Steering wheel
• Moves smoothly?
• Has correct free play?
• No strange noises? 
     
        
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417
4-3. Do-it-yourself maintenance
4
Maintenance and care
FuseAmpereCircuit
9DOME10
Foot lights, Vanity lights, Gauges and 
meters, Steering spot light, Steering 
switch illumination, Rear personal 
lights, Automatic transmission selec-
tor lever spot light, Front personal 
lights
10CDS10NOIS FILTER
11ABS MAIN210ECB system
12ABS MOTOR30ABS
13ABS MAIN110Capacitor
14E/G-B60FR CTRL BATT, ECTS and ALT-S
15ABS150VSC system, ABS MAIN1, ABS 
MAIN2 and ABS MTR
16RH J/B-B30AM2, DOOR FR, and DOOR RR
17VGRS40VGRS
18MAIN30H-LP R LWR and H-LP L LWR
19STARTER30Starting system
20LH J/B-B30FL DOOR, RL DOOR and RND 
NO.3
21P/ I - B60
Multi-port fuel injection system/
sequential multiport fuel injection 
system
22EPS80EPS 
23ALT150
RH J/B-AM, LH J/B-AM, E/G-AM, 
RR JB, HEATER, DEFOG, FAN1, 
FAN2, ABS2, ABS MOTOR, 
ABS MAIN1, and ABS MAIN2 
     
        
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421
4-3. Do-it-yourself maintenance
4
Maintenance and care
■Driver’s side instrument panel
FuseAmpereCircuit
1FR P/SEAT LH30Power seat system
2A/C7. 5Air conditioning system
3TV7. 5Audio system, Air conditioning sys-
tem, Rear view monitor system
4TRK OPN10Trunk lid opener
5LH-B10Theft deterrent system
6S/ROOF25Moon roof
7PA N E L7. 5
Steering switch illumination, Audio 
system, Glove box light, Automatic 
transmission selector lever illumina-
tion, Console box light, Adaptive 
variable suspension switch illumina-
tion, Cigarette lighter illumination, 
Air conditioning system, VSC off 
switch illumination, Driving pattern 
selector switch, Seat heater or 
Heated and ventilated seat switches, 
Register ILL RH, Register ILL LH, 
Register ILL CTR
8FUEL OPEN10Fuel filler door opener, Trunk lid 
opener 
     
        
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422
4-3. Do-it-yourself maintenance
FuseAmpereCircuit
9ECU-IG LH10
VSC system, ECB system, Yaw rate 
and G sensor, Steering sensor, 
Cruise control system, Dynamic 
radar cruise control system, EPS sys-
tem, VGRS system, Rear view moni-
tor system, Four-wheel drive system, 
Front controller, Moon roof, Rain sen-
sor
10FR S/HTR LH15Seat heater or Heated and ventilated 
seats
11RR DOOR LH20
Rear left door control system (Power 
door lock system, Door courtesy 
light, Power window)
12FR DOOR LH20
Front left door control system (Power 
door lock system, Power rear view 
mirror control system, Door courtesy 
light, Outside rear view mirror heater, 
Po w e r  w i n d o w )
13RAD NO.310Audio system
14H-LP LVL7. 5AFS, Automatic headlight leveling 
control system
15LH-IG10
Charging system, Headlight clean-
ers, Exhaust gas sensor, Rear window 
defogger, Electric cooling fans, Rear 
left door control system, Front left 
door control system, Emergency 
flashers, Automatic transmission, 
Seat belt pretensioners, Intuitive 
parking assist
16FR WIP30Windshield wipers and washer