We recently bought a 07 Suburban LT 1500 with 74k miles and are very happy after our first month of road trips. However, a few days ago the "Service Park Assist" message appeared at a stop light. The button on the lower dash was blinking and staying lit. Once I got home I tried a few things and found that the interior backup indicator lights and the sensors all worked when I was in reverse, giving me a warning within 1' of a trash can. The dash warning was gone and it seemed to have reset.
Now I get the "Service Park Assist" every time I use the brakes and clears when I go into reverse.
Is this a possible failure of the module or the trailer hitch wiring? All 4 sensors work as indicated by a click from each when in reverse. I inspected the harness and it appears unchanged from the factory with clips and ties still in place.
Thoughts?

 

Full range scan should show some codes in the U, B and C code families helping to point the way. Full scan is step one today in any shop with computerized vehicles.
Without a full scan your just throwing darts hoping for a bullseye.

 

I have a 2007 Chevy Avalanche LTZ,
I started getting a "Service Park Assist" fault on the dash display about a month ago.
The sensors work perfectly,
the above rear window lights come on at the appropriate times.
the warning tone comes on at the appropriate time
The fault pops up as I am driving in forward down the road ( when I assume Park assist should not even be active)
If I acknowledge it, it simply pops back up again
I cannot disable it with dash button ( button just blinks)
I have been to the local GM dealer and spent about $1,000 but they can not get rid of the fault.
work done thus far includes:
1) replaced the Park assist module from under the passenger seat ( then had to pay GM to enter in VIN number to address the replacement module) ( NO CHANGE )
2) replaced all 4 rear bumper sensors ( NO CHANGE )
3) replaced the rear bumper Park Assist wiring harness ( NO CHANGE )
4) codes have been read and or cleared numerous times ( NO CHANGE )
5) GM mechanic disconnected my rear lights and turn signal indicators as a test ( NO CHANGE )

They are charging me a small fortune but getting no where. I have no problem buying a part, but GM seems to have no idea what is wrong

I would appreciate any advise I can get