2008 Toyota Highlander Owners Manual - Page 244

2-4. Using other driving systems n If the "DAC"switch is turned off during operation of the downhill assist control system The downhill assist control system gradually ceases operation. The downhill assist control system indicator will flash during the cancelling operation, and then go off when the system is fully off. n Downhill assist control system operation sound A sound may be heard from the engine compartment during operation of the downhill assist control system. This sound does not indicate a malfunction. n When the downhill assist control system operates continuously The brake actuator may overheat. In that case, the system will cease operation and a buzzer will sound to alert the driver. Stop the vehicle in a safe place. (Do not continue normal driving.) n System malfunction l The downhill assist control system indicator does not come on when the "ENGINE START STOP" switch of the engine switch is turned to ON. l The downhill assist control system indicator does not come on when the "DAC" switch is pressed. In the above cases have your vehicle checked by your Toyota dealer. CAUTION n Conditions which may affect the downhill assist control system The system may not operate on the following surfaces, which may lead to an accident causing death or serious injury. l Slippery surface such as wet or muddy roads l Icy surfaces l Unpaved roads 214