Concerns about the stability of 4WDs have long bothered safety experts. 4WDs are high off the ground, have a tall body structure, and are usually designed to hold a lot of cargo. On many 4WDs built today, you will find warning labels notifying drivers of the SUV’s high centre of gravity handling characteristics.

The Lexus Hillstart/Downhill Assist Control System now provides the perfect answer to this. Lexus integrated this system into the RX330 and LX470 4WDs to put its drivers in complete control even in challenging off-road conditions.

During a downhill descent, normally a driver would put the transmission into low gear and use engine braking to slow the vehicle down. On steep hills, engine braking by itself may not be enough to slow the vehicle - and because of the attitude of the vehicle, stepping on the brakes can cause wheels to lock and the vehicle to become unstable. Enter the Lexus Downhill Assist Control system. While entering a very steep downhill grade, the driver simply needs to low gear, press a button, and sit back and relax. The vehicle will safely see you through.

The Lexus control system is easy for the driver. Turn the Downhill Assist Control switch on, put the transfer case in low range, make sure the vehicle speed is below 25 kph, and keep your foot off the accelerator and brake pedals. Now all the driver has to do is concentrate on steering.

During a DAC descent, the skid control computer calculates the vehicle speed, travel direction, and the gradient of the hill. Speed sensors and the yaw rate and deceleration sensor provide the information, while the computer automatically applies the appropriate wheel brakes to keep the vehicle stable and slow it down to between 5 and 7 kph. Driving down steep grades can be tricky, but backing down one is even harder. For that occasional time when the 4Runner’s four-wheel drive system can’t quite pull it up a steep grade, the DAC system also works in reverse. When the vehicle is backing down the hill, the DAC system keeps the vehicle speed between 3 and 5 kph.

Another Lexus system that helps drivers both on and off road is the Hill-start Assist Control and it works automatically as long as the transmission shift lever is in any forward gear position. If you have ever had to juggle the brake and gas pedals to start a vehicle moving while it was sitting on an uphill grade, you will appreciate HAC. The system prevents the vehicle from rolling backwards by applying the brakes for up to five seconds after the brake pedal is released. Now the driver can press on the throttle in a relaxed manner without concern that the vehicle will roll.

When Hill-start Assist Control activates, a flashing Vehicle Stability Control indicator and a buzzer notify the driver. The rear brake lights are also turned on when pressure is applied to a caliper to notify drivers behind that the vehicle is stopped.

A new design wheel speed sensor is a key component of both Downhill Assist Control and Hill-start Assist Control. Magnetic resistance element (MRE) rotation sensors can detect wheel speed down to almost zero, compared to conventional inductive magnetic sensors that can typically only measure accurately down to about 5 kph. The MRE sensors can also indicate the direction of wheel rotation. So with Lexus Control Systems you can confidently tackle steep inclines with total confidence.

Lexus vehicles are brought to you in Oman by Saud Bahwan Group – along with special benefits and privileges such as a 6 years unlimited extended mileage protection – AMAN BAHWAN and Lexus Prestige Club Card that offers 24 hours on-road assistance from AAA, shopping discounts from premium outlets and more. During Ramadhan, Lexus showrooms will remain open till midnight on weekdays and from 7.00 to midnight – even on Fridays.

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