Lexus RX Owners Manual (RX450h): Selecting constant speed control mode

When constant speed control mode is selected, your vehicle will maintain a set speed without controlling the vehicle-to-vehicle distance. Select this mode only when vehicle-to-vehicle distance control mode does not function correctly due to a dirty radar sensor, etc.

1. With the cruise control off, press and hold the "ON/OFF" button for 1.5 seconds or more.

Immediately after the "ON/OFF" button is pressed, the radar cruise control indicator will come on. Afterwards, it switches to the cruise control indicator.

Switching to constant speed control mode is only possible when operating the lever with the cruise control off.

2. Accelerate or decelerate, with accelerator pedal operation, to the desired vehicle speed (at or above approximately 25 mph [40 km/h]) and push the lever down to set the speed.

Cruise control "SET" indicator will come on.

The vehicle speed at the moment the lever is released becomes the set speed.

■ Dynamic radar cruise control with full-speed range can be set when

• The shift lever is in D or range 4 or higher of S has been selected.
• Range 4 or higher has been selected by using the paddle shift switch.

  (vehicles with paddle shift switches)

• Vehicle speed is at or above approximately 30 mph (50 km/h). However, when a preceding vehicle is detected, the dynamic radar cruise control with full-speed range can be set even if the vehicle speed is below approximately 30 mph (50 km/h).

■ Accelerating after setting the vehicle speed The vehicle can accelerate by operating the accelerator pedal. After accelerating, the set speed resumes. However, during vehicle-to-vehicle distance control mode, the vehicle speed may decrease below the set speed in order to maintain the distance to the preceding vehicle.

■ When the vehicle stops while follow-up cruising

• Pushing the lever up while the vehicle ahead stops will resume follow-up cruising if the vehicle ahead starts off within approximately 3 seconds after the switch is pressed.
• If the vehicle ahead starts off within 3 seconds after your vehicle stops, follow-up cruising will be resumed.

■ Automatic cancelation of vehicle-to-vehicle distance control mode Vehicle-to-vehicle distance control mode is automatically canceled in the following situations.

• Actual vehicle speed falls below approximately 25 mph (40 km/h) when there are no vehicles ahead.
• The preceding vehicle leaves the lane when your vehicle is following at a vehicle speed at or below approximately 25 mph (40 km/h). Otherwise, the sensor cannot properly detect the vehicle. ("Radar Cruise Control Not Available No Preceding Vehicles" is displayed on the multi-information display)
• VSC is activated.
• TRAC is activated for a period of time.
• When the VSC or TRAC system is turned off.
• The sensor cannot detect correctly because it is covered in some way.
• Pre-collision braking is activated.
• The parking brake is operated.
• The vehicle is stopped by system control on a steep incline.
• The following are detected when the vehicle has been stopped by system control:
  • The driver is not wearing a seat belt.
  • The driver's door is opened.
  • The vehicle has been stopped for about 3 minutes

If vehicle-to-vehicle distance control mode is automatically canceled for any other reason, there may be a malfunction in the system. Contact your Lexus dealer.

■ Automatic cancelation of constant speed control mode Constant speed control mode is automatically canceled in the following situations:

• Actual vehicle speed is more than approximately 10 mph (16 km/h) below the set vehicle speed.
• Actual vehicle speed falls below approximately 25 mph (40 km/h).
• VSC is activated.
• TRAC is activated for a period of time.
• When the VSC or TRAC system is turned off.
• Pre-collision braking is activated.

If constant speed control mode is automatically canceled for any other reason, there may be a malfunction in the system. Contact your Lexus dealer.

■ Warning messages and buzzers for dynamic radar cruise control with full-speed range Warning messages and buzzers are used to indicate a system malfunction or to inform the driver of the need for caution while driving. If a warning message is shown on the multi-information display, read the message and follow the instructions.

■ When the sensor may not be correctly detecting the vehicle ahead In the case of the following and depending on the conditions, operate the brake pedal when deceleration of the system is insufficient or operate the accelerator pedal when acceleration is required.

As the sensor may not be able to correctly detect these types of vehicles, the approach warning may not be activated.

• Vehicles that cut in suddenly
• Vehicles traveling at low speeds
• Vehicles that are not moving in the same lane
• Vehicles with small rear ends (trailers with no load on board, etc.)

• Motorcycles traveling in the same lane
• When water or snow thrown up by the surrounding vehicles hinders the detecting of the sensor
• When your vehicle is pointing upwards (caused by a heavy load in the luggage compartment, etc.)

• Preceding vehicle has an extremely high ground clearance

■ Conditions under which the vehicle-to-vehicle distance control mode may not function correctly In the case of the following conditions, operate the brake pedal (or accelerator pedal, depending on the situation) as necessary.

As the sensor may not be able to correctly detect vehicles ahead, the system may not operate properly.

• When the road curves or when the lanes are narrow

• When steering wheel operation or your position in the lane is unstable

• When the vehicle ahead of you decelerates suddenly