Hi all. I recently bought an FR-V. The previous owner said the parking sensors stopped working years ago. I thought I'd look at it and try to figure out what the problem was. The symptom was; When placed in reverse the system would make its startup beep followed by a constant tone for about 30 odd seconds before going silent. The first step was to confirm the parking sensors were all working. Turn the ignition on but do not start the engine. Place the car in reverse gear. One by one bring your ear up to each sensor. You should hear a ticking noise if it's working. Mine all were, though I noted they seemed very quiet. For good measure I got under the car, unplugged the sensors and squirted some WD-40 in each connector block to ensure the connections were sound. Now it was time to hunt for the controller. I followed the wiring loom which you can see in the back wall of the spare wheel well. The controller is mounted behind the offside boot panel, just below the speaker. You must first remove the alarm sounder. Remove the bottom bolt and loosen the top two using a 10mm socket. Simply slide upwards to remove and then unplug the connector. The controller can now be removed by removing the three 14mm nuts and reaching behind the cavity to get it out. You will find a Bosch controller. I investigated the wiring connectors. Their functions are as follows. Black connector. Power feed in 0V = Black, + = Brown/red stripe, sounder feed = Green & yellow . Brown connector. Red & Yellow/green = Common power feed to all parking sensors. The remaining 4 cores are the sensor return signals, one from each sensor. The sounder is mounted just inside the boot pillar. The connector feeding it can found on the wiring loom. The positive power for the controller is fed directly out of the reverse light bulb feed. The negative supply can be seen as the top black core bolted down with all the other negative wiring near where the controller was mounted. I used a voltmeter to confirm that the supply to the unit was good, it was 10.5V odd which is probably fine. This points unfortunately to a failed controller. The unit is a Bosch 0263004147. This one was manufactured in August '07. Disappointing considering it is something that is only powered up very occasionally. I suppose I'll have to keep my eye on fleabay for a controller and hopefully once replaced the actual sensors will be fine. I'll update as and when I get it swapped.