What Causes Parking Radar System Failure?
4 Answers
Parking radar system failure can be caused by incorrect sensor installation, presence of foreign objects, high temperatures, and other reasons. The specific causes are explained as follows: Incorrect sensor installation: Incorrect sensor installation, detachment, or damaged sensors. Inspect and repair the sensors, and replace them if damaged. Presence of foreign objects: Foreign objects can cause the radar to be unresponsive. Remove the foreign objects to resolve the issue. This may lead to misalignment of the parking position, resulting in scratches or other damage to the vehicle. High temperatures: High temperatures can affect the environmental adaptability of the reversing radar, impacting the sensitivity of the sensors and the normal response of the processor. Move the vehicle to a shaded area before using the radar.
When encountering parking radar failure, I think the most common issue is with those small black circular sensors. During regular car washes, if the water pressure is too high or wind and rain carry sand and mud onto the sensor surface, mud spots or ice buildup can prevent ultrasonic signals from being emitted. Another scenario is lightly bumping the rear bumper against a wall corner—though the bumper isn't damaged, a loose sensor clip inside can cause false alerts. My friend's car had this issue last time; the radar kept beeping randomly, and a shop inspection revealed the right rear sensor connector was half loose. Wiring aging is also common, especially with frequent trunk openings where wires inside are prone to bending. Some older cars may even have water leakage in the trunk damaging the wiring. Lastly, it's worth checking blown fuses, particularly during summer when high temperatures increase electrical load and risk melting them.
Regarding the failure of the reverse radar, I have encountered it several times and found that wiring issues are the most troublesome. Especially at the corner of the wiring harness connecting the rear bumper to the car body, the repeated opening and closing of the trunk can cause the wires to bend repeatedly, leading to the copper strands inside gradually breaking and causing poor contact. There is also the issue of unstable power supply to the module; when the car battery voltage is low or the alternator is not working, the radar system will directly go into sleep mode and not start. Additionally, I would like to remind owners who have installed aftermarket radar kits—I have tried those cheap kits, and the sensors and control box often don’t match, resulting in frequent false alarms. For newer cars, software issues should also be noted; during the upgrade of the car’s head unit, the radar driver might be lost. These faults are not complicated to fix, but a diagnostic computer needs to be connected to the OBD port to read the specific error codes.
Radar suddenly failing usually boils down to four key areas. First, the sensor itself might be damaged—high-pressure car wash jets or small stones can crack the sensor housing. Second, wiring issues are common, like rodents chewing through cables or trunk water leaks corroding connectors, leading to short circuits. Controller malfunctions also occur frequently, especially after summer heat exposure or water submersion frying circuit boards. Lastly, don’t overlook reverse light signal problems—the radar system needs to detect the reverse gear signal to activate. For quick fixes, gently clean sensors with a soft cloth or disconnect the battery to reboot the system. If repeated restarts don’t work, professional equipment is needed to test power and signal line waveforms.
