We bought our Toyota Vios from Toyota Lanna over twelve months ago. Two front sensors and four rear sensors were fitted. From the start we had problems with the right front sensor. We complained about it at every service. They initially changed the right to the left. While this seemed to help, the problem persisted. Lanna have eventually acknowledged the sensor is faulty and have ordered new parts from Bangkok which will be fitted next week. Hopefully the sensors will then work well!