HELP! Car Warranty Invalid If They Can’t Find The Issue?

Skuk

Grey_Critic said:

And assuming that the additional hours asked for does not resolve the problem how many more hours should the OP be asked to approve - 5 - 10 - 20?

Seems to me there is a lack of competency on behalf of the dealership.

facade said:

You get messages like this when the front facing camera or radar module is obscured by dirt or not working, but you'd expect that to be the first thing they would check.

However from t'interweb

If your vehicle is not under warranty, the following tips will, in most cases, help fix the Active Brake Assist Functions Limited warning. 

1. Remove all dirt and snow from the front windshield, grill, and bumper. 
2. Activate transport mode and drive vehicle for approx 10 km. The DTC then switches to passive, and the sensor can be calibrated. The Active Brake Assist should recalibrate automatically, and the error clears on its own if the code was due to a dirt issue.
   

I've no idea what DTC is, or how to activate transport mode though.

Exactly, there’s no limit to how many hours they could add on to find the problem. 

UPDATE: I asked for what they have been doing in the hour they worked on the car and if they had tried to clean the sensor. No response to this. 

They listened to my calls and there was no conversation/evidence where I had approved any costs so they agreed to give me the car back atNO COST to myself.

Funnily enough, the guy said they’ve just done a complimentary jet wash and hoover and then mentioned he’d drove the car around and the message has gone. I believe the jet wash probably managed to clean the sensor after all that! 

Thanks for your help all.