What is the reason why all the reversing radars of Volkswagen Lavida are not working?

[JaceDella]

If all the reversing radars of Volkswagen Lavida are not working, it may be due to loose wiring connections or sensor malfunctions. Below is more information about reversing radars: 1. Introduction: The reversing radar, also known as "reverse anti-collision radar" or "parking assist device," mainly consists of ultrasonic sensors, a controller, and a display. 2. Working principle: When reversing, the reversing radar uses ultrasonic technology. The probes installed on the rear bumper send ultrasonic waves that reflect off obstacles, calculating the actual distance between the vehicle and the obstacle. This information is then provided to the driver, making parking or reversing easier and safer.

[VanTalia]

Last time I repaired a Volkswagen Lavida with all radar sensors not working, the owner was really anxious. The main causes fall into three categories: hardware issues like all the sensors being covered in mud, making them unable to send signals when reversing; power supply problems such as a blown fuse—check the one labeled F28 in the driver-side fuse box; or corroded/loose wiring connectors, especially the trunk wiring harness connectors which are prone to oxidation. When fixing it, you need to test step by step, using a diagnostic tool to read fault codes. If it shows module communication failure, check the radar control unit voltage—if it's around 10 volts or more, the sensors are likely dead. Don’t delay too long; driving without radar increases the risk of scratches when reversing. A professional shop can fix it in about half an hour.

[VanEsther]

My Lavida also had that issue where all the radars suddenly stopped working, which really scared me. At first, I thought the car settings might have been accidentally turned off, like disabling the assist functions in the central control, but adjusting them didn’t help. Later, a friend suggested checking from the outside—cracks or water ingress in the sensors could cause complete failure, and a short circuit in the wiring might trigger the system’s automatic power-off protection. It’s best to first crouch behind the car and check if the sensors are clean, as water stains can easily hide there after rain. If that doesn’t work, take it to a shop to see if the control module is burnt out—these electronic parts can fail after prolonged use. Replacing them with original parts isn’t expensive, and after the repair, reversing feels much safer.

[Nunes]

The reversing radar system of the Lavida is actually quite sophisticated, and complete failure usually occurs at key components. One is the host controller malfunction—if the module crashes, it won't receive signals from the sensors. Another is wiring issues, such as aging or exposed main harnesses or loose connectors. During inspection, focus on the control box under the front passenger seat; if there's no output when tested with a multimeter, replace the module. For prevention, dry the sensors after washing the car, as Volkswagen designs have small gaps prone to dirt buildup. If a malfunction occurs, avoid forcing reverse—safety first.