Hello, I bought a used 2018 Outlander Sport a few weeks ago. It was equipped from the factory with the backup sensors (its on the original vin window sticker). When I first got it, it beeped like it should. Now it does not beep at all except for the initial "put in reverse" beep. I cleaned the sensors with a microfiber cloth (were not really that dirty). While looking into this I noticed that the bumper has either been replaced and painted or just repainted (very small overspray on some of the black plastics). So my questions:

1. Is there a way I could have disabled it by accident.
2. From what little info I can find online, it seems there is a box in some Mitsu's that can enable/disable the sensors in the cargo area, is this true and where is it on the Sport?
3. Are these sensors painted from the factory? All 4 or just 2 like mine are?

Just trying to figure some stuff out before I end up taking it in to the dealership. Its under warranty (not just factory, but from Carvana as well) but if its something I can fix easily myself I will. Thanks!

 

I have installed myself front and rear ultrasonic backup system (#869 here) on my Outlander Sport (RVR here in Canada), so I may have some degree of knowledge concerning backup sensors.
At least for earlier model years the parking assist system was only a dealer installed accessory and not from the factory. This would mean that the control box can be located anywhere but most likely in the trunk somewhere.
Testing whether your system is factory installed or not is relatively easy. Open up the tailgate and find the access to the backup lights. If you see in either side a wire(s) tapped/spliced to the reverse light wires close to the bulb then the system is aftermarket (dealer installed).
The fact that you hear a sound when putting into reverse indicates that your speaker is good and the power from the reverse light goes to the control box and from it to the speaker. Since none of the sensors detect proximity of the objects it is more than likely that the sensors are OK. Dust or any surface contamination barely effects the detection. My best guess is that the control box may have become defective. Nonetheless, you must locate the box and test the connections. If my prediction is correct you can buy the entire system very cheap from ebay ($10 or so, see my post from the above link) and install it yourself. I have them over two years and work flawlessly front and back. If you are lucky you may only need the control box to be replaced. The sensors are paintable and the ones from ebay come in few different colors. Good luck!