Joe Goldstein

My wife and I purchased the Q8 recently with the intention of carrying her electric wheelchair on the back. We have an electric ramp to tote around the chair and have used this and ramps like it on multiple vehicles over the years. The Q8 is once again at the dealership (it has spent almost more time there than in my garage) because the sensors continue to fail. The BLISS sensor activates without another vehicle near the car (this, in turn, makes the wheel hard to turn when changing lanes), the sign reading feature fails, and the adaptive cruise control goes offline and will not come back, and the pre-sense functionality stops working. Posting here in hopes of finding other handicapped drivers that may use a wheelchair ramp on their Q8 to see if they might be having a similar experience. The dealership is telling me that extra weight on the back is messing up the lasers which in turn is shutting down multiple systems. I have had other vehicles with adaptive cruise, bliss, accident avoidance, etc and have never had this issue while using the ramp for the wheelchair.

Any advice or input would be greatly appreciated.

McGriddle

Do you have any details of the ramp or a description of the weight, etc? Audi Side Assist and Pre-sense in the front and back use radar (and the front camera) and not lasers, though LIDAR is used for active steering and such. Were these systems working fine before the install of the ramp? Not sure if weight is the issue here as opposed to a specific system problem that they should be able to fix.

Joe Goldstein

The ramp is a standard Harmar 500 and weighs approx 115lbs with the swing away arm that is attached. The chair comes in around 200lbs including batteries and seat. We have had the ramp on the vehicle from the day we picked it up.

tomk

What does your driver side B-piller say your Gross Vehicle Weight Rating (CVWR) is? Add the weight for passenger and driver subtract from the CVWR number and that is the number of pounds of cargo & luggage (ie wheelchair equipment) you can carry. Also note the Q8 can carry a tongue weight of 770 lbs and your load is not that heavy.

McGriddle

Agreed. It doesn't seem that the ramp plus chair is too heavy. It seems like the dealer is just using that as an excuse.

Joe Goldstein

Dealer just called and stated that the issue is the weight of the ramp is causing the suspension to throw pre-sense codes and this is why we are having the issues we are having. If there is a tongue weight of 770 and we are at approx 50% of that weight, would it be unreasonable to think that the suspension is not at issue?

tomk

Refer to pages 115-116 in your owners manual. On page 294, it will state the permitted load on the rear axle as found on the safety certificate on side area of door on driver's side.What is your's? Note if you have air suspension, you could apply MMi>Vehicle>setting & Service>Air suspension>trailer, after selecting Comport mode, to see if that helps.

Joe Goldstein

Thanks to all for your replies. @tomk I will check this when we pick up the vehicle today. As I understand this, if the weight of the chair and ramp fall below this rating, the vehicle should be able to operate properly. Their reasoning also does not address why the BLISS alert comes on at random times as I would not think this would have much to do with the load on the back of the vehicle.

tomk

I agree, load weight is not any where near the limits for the vehicle.

tomk