Volt Parking Sensors Dead, Repair Guide & Solutions

Had a similar issue with my 2014 Prius Hybrid (also happened to my cousin's Prius V). The parking sensors and proximity sensors completely died, no beeping, no warnings, nothing. With some experience working on hybrid vehicles, I've seen this a few times. Turned out to be a loose connection in the wiring harness going to the ultrasonic sensors. The workshop found that moisture had gotten into one of the connectors, causing intermittent failures before completely stopping. They cleaned the connections, replaced a damaged plug, and resealed everything properly. Total repair came to 95 Euro, mostly labor costs. A few questions about your Volt to better help: Are all parking sensors dead, or just some? Did it fail suddenly or gradually get worse? Any recent car washes or exposure to heavy rain? What's the error code you're getting? The rearview camera system still working normally? Sometimes these systems are linked, so it helps narrow down if it's a sensor issue or broader electrical problem.

Thanks for the response. Last service was at 43985 KM. All the blind spot sensors and obstacle detection stopped working at once, it was pretty sudden right after a heavy rain storm. The rearview camera works fine though. The error code is B21A4. Really hoping it's just faulty wiring or water damage like in your case and not a complete parking assist module failure. I've checked and none of the external sensors look physically damaged. Currently getting no response at all from any of the proximity sensors during parking, no beeps, no display warnings, nothing. But considering the timing with the rainstorm, moisture in the connectors sounds like a likely culprit. Good to hear your repair costs were reasonable. I'll have the shop check the wiring harness first before replacing any components.

Thanks for the extra details about the timing with the rainstorm. Definitely mirrors what happened with my Prius system. The working rearview camera but completely dead sensors matches my experience too, it's a good sign that points to sensor/wiring issues rather than a failed control module. I had my mechanic trace the faulty wiring harness from the obstacle detection sensors, they found corrosion in multiple connector points after that big storm. The parking assist system is pretty sensitive to any breaks in the circuit. Would bet your B21A4 code is triggered by the same water infiltration issue. Quick tip from my repair, have them check the main harness junction points first, especially near the wheel wells where water tends to collect. The ultrasonic sensors themselves were fine in my case, just needed to clean/reseal the connections and replace one corroded plug. Much cheaper than swapping the whole parking assist control module. Should be a straightforward fix like mine was, especially since the timing matches up with weather exposure. The separate rearview camera system still working properly is another good indicator it's just wiring.

Thanks for the detailed advice. I'll definitely get the shop to focus on checking those wiring harness connection points first, especially around the wheel wells where that rainstorm water probably collected. Makes total sense about the ultrasonic sensors being sensitive to circuit breaks from moisture. The B21A4 code and symptoms match what you experienced, complete failure of all proximity sensors but working rearview camera. Really hoping it's just corroded connectors that need cleaning and resealing rather than replacing the whole parking assist control module. Will have them trace the wiring harness carefully when I bring it in next week. Good tip about checking the main junction points first. The timing with that heavy rain definitely suggests water damage rather than sensor failure. I'll update once I get the repair done, but feeling more confident now that it should be a relatively straightforward and affordable fix like yours was.