Park Assist issue

[Dunc77]

Hi,

I hope you can help, this is a complicated one to explain. The parking sensors on my 2015 A4 work but have a specific issue... when I start the car and select reverse, the park assist initialises, the proximity is displayed on the MMI and all looks fine. When I then select drive, the MMI still displays the proximity but no beeps. If I switch park assist off then on (still in drive) it starts beeping again. If I then select reverse, the beeping stops. If, at the end of a journey I select reverse, the park assist activates and beeps if there are objects around but if I want to park forwards, there are no beeps or proximity does not display on MMI. However, if press the park assist button it initialises. Both front and rear sensors work fine once initialised but I can't think what might cause this. Any ideas?

Thank you,

Dunc.

[Sid2020]

I think what you might be referring to is common on previous generation parking systems. The front sensors only activate when in reverse and stop when in drive or 1st unless you manually activate the system. The Idea I surpose was that if reversing you might not be watching the front for swing angle so sensors might save a scrap but when driving forwards we’re not of much use, but This was changed on newer generations and front sensors work in any gear below something like 10mph 

[Steve Q]

You could always get a diagnostic check to see if any fault codes flag up 

[Sid2020]

Never a bad idea to get a scan, pdc sensors usually throw one of 3 faults, short to ground, circuit open or no communication. Any one of these in a single sensor will stop the system working and so you would get a warning message on the mmi when system activates. I would be looking for a missing message issue between 2 modules relating to the pdc and gear selection/speed as if there working but not how you think they should