Sonar System Alert

Wonder if anyone can shed some light into why my 2020 TRD OR this morning suddenly fired code/ warning. 'A Malfunction in the Sonar System has been detected.....'

It seems my rear bumper sensors suddenly crapped out. It is raining, it happened on a 5 min drive to drop my daughter at school.

Anyone have any idea if its something I can do outside the dealer?

Thank you

 

It's under warranty, let the dealer inspect it.

 

Unfortunately I'm at 41K miles.......

 

A call to local, independent shops to ask "I am having issue with a 2020 Tacoma TRDOR with the Sonar System - can you do diagnostics? How much do you charge for a 1 hour check and advise?" would be how I'd roll. Get a diagnostic from them or the dealer with the same verbiage and then ask the forums if anyone else has had that specific issue causing the fault and what repairs are like if done yourself and compare to the estimate the local or dealer provides based on their 1 hour look.

Pretty hard to diagnose a sensor issue (or maybe not) from hundreds to thousands of miles away without vehicle in hand.

 

I have had this exact issue happen when it was raining or right after. I resolved it by turning off the BSM, then cleaning the BSM sensors in the rear bumper. They are located inside the bumper, so you'll have to crawl/reach underneath your truck. I used an old kitchen towel to wipe them off. Some dirt/mud/road tar got onto them. It was blocking the signal. After I wiped it down, I turned the truck back on and turned the BSM back on. Problem solved.

Also, while you are down there cleaning, check the cables and the connectors. Make sure they are not frayed or damaged. A loose or damaged connector can also be the cause of this error.

 

I had something similar once with my BSM. I shut off the truck (I was at my destination) and it has never returned since and still functions fine.

 

Good to know..... going to clean them out from behind thoroughly, hopefully it will resolve it. I did do a shut off etc initially but nothing.

Odd it's never done it before, but considering we've had no rain all summer in the Northeast/ New England, the truck doesn't know how to behave with the copious amounts rain today.

 

Cleaned them thoroughly, all look ok front and inside of bumper and still triggering fault. Will wait a few days see if they have water in them and hopefully dry out. Not sure if there's a way to test them individually.

 

Make sure to put some dielectric grease on the plugs before you put them back together. That will help with keeping moisture out of the connections.

 

This. The rear body harness runs the wiring for the rear bumper, including the sonar and BSM sensors. The early 3rd gen 2016-2017 had issues with water getting into the harness but Toyota changed how they were built and solved the problem at least for that failure mode. Is check the rear body harness connector (very aft end of drivers side frame rail - there are usually two plugs). Unplug, inspect for moisture or corrosion, clean/dry as necessary and pack with dielectric grease and reconnect. If that doesn't fix it and it's rain related, there could be water in the harness elsewhere or at the sensors themselves.