2005 Toyota 4Runner Owners Manual - Page 190

'05 4Runner_U (L/O 0409) If the warning light blinks: The tire pressure warning system may be malfunctioning. Contact your Toyota dealer. SYSTEM MALFUNCTION The tire pressure warning system does not function properly under certain circumstances. In the following cases, the low tire pressure warning light may not come on even if the tire inflation pressure is low, or it may come on when the tire inflation pressure is actually normal. CAUTION D The use of non−genuine wheels will cause the air pressure sensors to transmit the electronic code in different manner, resulting in the system failure. D The use of different type of tires with genuine wheels may also cause the malfunction of the system. D Electric devices or facilities using similar radio wave frequencies are nearby. D A radio set to similar frequencies is in use. D A lot of snow or ice covers the vehicle, in particular, around the wheels or wheel housings. D The tires are not equipped with an air pressure sensor. D D D D Snow tires or tire chains are used. Non−genuine Toyota wheels are used. The sensor battery is expired. Radio waves from the air pressure sensor installed on the spare tire cannot be received. 190 2005 4RUNNER from Sep. '04 Prod. (OM35843U)