2003 Toyota Prius Owners Manual - Page 181

If your hybrid system stalls while driving130. If your hybrid system stalls while driving...1. Reduce your speed gradually, keeping a straight line. Move cautiously off the road to a safe place. 2. Turn on your emergency flashers. 3. Turn the ignition switch to "OFF" position, and try starting the hybrid system again. If the hybrid system will not start, see "If your vehicle will not start" on page 170. 131.If your vehicle overheats If your high coolant temperature warning light comes on, if you experience a loss of power, or if you hear a loud knocking or pinging noise, the hybrid system has probably overheated. You should follow this procedure...1. Pull safely off the road, stop the vehicle and turn on your emergency flashers. Put the transmission in "P" and apply the parking brake. Turn off the air conditioning if it is being used. 2. If coolant or steam is boiling out of the radiator or reservoir, stop the hybrid system. Wait until the steam subsides before opening the hood. If there is no coolant boiling over or steam, leave the hybrid system running and make sure the electric cooling fan is operating. If it is not, turn the ignition off. 3. Look for obvious coolant leaks from the radiator, hoses, and under the vehicle. However, note that water draining from the air conditioning is normal if it has been used. CAUTION When the hybrid system is running, keep hands and clothing away from the moving fan and engine drive belts. 4. If the coolant is leaking, stop the hybrid system immediately. Call a Toyota dealer for assistance. 5. If there are no obvious leaks, check the coolant reservoir. If it is dry, add coolant to the reservoir while the hybrid system is running. Fill it about half full. CAUTION If the hybrid system is not operating, the power assist for the brakes and steering will not work so steering and braking will be much harder than usual. CAUTION To help avoid personal injury, keep the hood closed until there is no steam. Escaping steam or coolant is a sign of very high pressure. CAUTION Do not attempt to remove the radiator cap when the hybrid system and radiator are hot. Serious injury could result from scalding hot fluid and steam blown out under pressure. 174