2007 Toyota Prius Owners Manual - Page 348

Electric power steering system The electric power steering system, using an electric motor, assists the turning of the steering wheel. In the following cases, you may feel the steering becomes heavy. However, the electric power steering system warning light does not come on. (Because it is not a malfunction.) Brake pad wear limit indicators D When the 12 volt battery is discharged Check the 12 volt battery's condition. If necessary, recharge or replace the battery. For details, see "Checking 12 volt battery condition" on page 418. D When the steering wheel is operated with the hybrid system not to be turned on (with the "READY" light off) The 12 volt battery capacity is decreased temporarily. The system returns to normal some time after the hybrid system is turned on. If there is a problem somewhere in the electric power steering system, the warning light comes on in the multi −information display. For details, see "Multi −information display" on page 133. When you move the steering wheel, an electrical motor noise may be heard. This is power steering motor noise, and is not a malfunction. 30p003 D When maneuvering the steering frequently or keeping the steering wheel turned fully while the vehicle is stopped or moving very slowly The power steering effect will be reduced to prevent the system from overheating. Avoid turning the steering wheel, or stop the vehicle. When you leave the vehicle in the "IG−ON" mode for a while, the system will become cool. The brake pad wear limit indicators on your disc brakes give a warning noise when the brake pads are worn to where replacement is required. If you hear a squealing or scraping noise while driving, have the brake pads checked and replaced by your Toyota dealer as soon as possible. Expensive rotor damage can result if the pads are not replaced when necessary. NOTICE If you repeat the operation which will turn on the overheating prevention function, the electric power steering system may be damaged. 331