What Causes Car Radar to Not Alert?
3 Answers
It may be caused by the power supply or ground circuit of the parking radar system not functioning properly. Common fault points include a missing power supply to the parking radar controller, loose connections in the radar probe plug, or damage to the buzzer or loose connections in its plug. When troubleshooting, it is necessary to refer to the circuit diagram of the relevant vehicle model to locate the corresponding lines. Here is additional information: Parking Radar: The full name of the parking radar is "Reverse Anti-Collision Radar," also known as a "Parking Assistance Device." It mainly consists of ultrasonic sensors, a controller, and a display (or buzzer). When the gear lever is shifted into reverse, the parking radar automatically starts working. When the radar detects an obstacle too close behind, the buzzer or display device of the parking radar will issue a warning to remind the driver to pay attention to the distance behind.
I just bought a car with a rear parking radar last year, and found that sometimes the radar doesn't beep at all, almost hitting objects. At first I thought the radar was broken, but upon closer inspection, I realized all the small circular sensors on the bumper were covered in mud. Cleaning them fixed the issue. Don’t forget to check these areas after daily driving, especially during long trips in the rainy season, as dirt buildup can quickly affect the signal. Additionally, the radar system might be connected to the battery, and low voltage in winter could also cause malfunctions. Personally, I make it a habit to wipe the sensors every time I wash the car, using a damp cloth gently to avoid scratching them with hard objects. Safety first—if cleaning doesn’t help, then take it to a professional repair shop.
From an electrical circuit perspective, a car radar's failure to alert is mostly due to sensor issues or wiring faults. Sensors are like tiny eyes; they go blind when blocked by dust or rain, so clean them promptly. Loose connections or blown fuses can also interrupt signal transmission. For example, my relative's car had a sudden radar malfunction, and upon inspection, we found a loose wiring connector in the trunk. It's advisable to open the hood or fuse box and first check if the radar-related fuses are intact—replace them if they've changed color. If you're handy, you can try fixing it yourself, but avoid disassembling randomly as unstable voltage might damage the system. If all else fails, it's best to visit a 4S shop for diagnosis.
