the PDC light in the front (module A169) stays off, when system is off... turns on either manually or with gear in reverse, with a slight delay, to avoid false activations when you move gear selector from P, passed R to D... when sonar system detects obstacles, the speakers beep, the light stay solid on. if the light is blinking, something is wrong with the system... I just started my INPA to troubleshoot my problems, and it seems that IMPA is capable of testing the PDC module, probably tell you which sensors is bad, if any...

since the PDC module is in the trunk, it is a good idea to check it for water damage...

Fuse F6 will kill PDC along with couple other modules, such as electrochromatic mirror, tire pressure monitor - if your car never had them, nothing to worry about...

ep - you mentioned that your front license plate bracket covers one of the sonic sensors?... if I remember correctly, the OE front bumper of the 4.6iS has a small notch/cutout, not really visible, about 1cm wide, maybe 1mm thick, and the license plate brackets, both US and EU plates have a little tab - when you put the plate holder against the bumper and slide it left/right in search of the center, the tab slides into the slot and - voila!!! here is your center, and the sensors are not blocked... is your bracket off center?

EDIT: these are OE front license plate brackets, both EU, one is for 4.6iS with the center notch (has a license plate still attached) and the other one is for the 4.8iS, no little tab to locate center on the bumper... both bought from US dealers, at different times, both about $20-25 a piece...

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