Peterjay1004

Any suggestions/comments on the following would be appreciated. I recently bought a 2008 GS 450h Sports model with 54,000 miles. This is a new Japanese import. UK registration complete. Speedo converted to MPH and replacement English centre console fitted. Car drives perfectly but it does have two faults. One, the tyre pressure warning light is permanently on although the tyres are new and correctly inflated. Two - and I think this is more important, the PCS light together with a red warning triangle comes on whenever I reach 43 MPH. These lights stay on until I switch off the engine when, presumably the system re-sets. I can drive indefinitely below 43 MPH and the lights don't come on. The diagnostic machine at the garage I have used for decades read all the systems on the car but did not show any fault codes except the tyre pressure sensor. Here's a couple more odd features of the car that may or may not be related to the PCS problem. Driving away after starting the car does not lock the doors until the car is traveling at about 25 MPH. With all my previous cars with this feature the doors locked at around 5 - 7 MPH. On one occasion last week I had to brake a little harder than normal but this was not an emergency and there was zero chance of an accident but to my surprise the seat belt tensioners operated.. On another occasion I accidentally turned on either the parking sensors or the lane guide. The approach to my house is a narrow lane with a sharp corner edged with a wall. I might have expected a warning sound but not the loud warning buzzer and a flashing message to brake as the car passed the wall.. I have no idea what is causing the PCS fault light or why the diagnostic machine doesn't find the fault. I wondered if there is a faulty speed sensor relaying wrong information and the mechanic at my garage suggested that the device fitted to alter the speedo from km to MPH is faulty or fitted incorrectly.. Any suggestions please. I read a thread recently where somebody with a similar fault was encouraged to spend several thousands by his Lexus dealer on new PCS parts that might or might not fix the problem. I have no intention of going down that route but I would like to fix this on what is otherwise a truly awesome car.