Toyota RAV4 Forums banner
1 - 2 of 2 Posts

·
Registered
Joined
·
23 Posts
Hi guys! i have a 2020 toyota rav4 le i got the same issue to everyone else that my battery got dead by parking it overnight. today my car wont start i have this problem ever since july but it happen today which happen to me twice between that july-sept. does anyone know what really costing the draining the battery of rav4? because what read all the comment was turnoff the parking brake and update the DCM firmware? anyone have idea?
See this thread: Rav4 2020 LE Battery drained out for no reason
 

·
Registered
Joined
·
23 Posts
I posted the below message seven months ago on the "LE Battery dead" tread, but I thought I would update it to say that since the ECU was replaced in the Spring of 2020, I have had no other issues with the battery.
-------------------------------------------------------------------------------------------------------------------
Hi, just thought I would share my experiences in this area with my gas 2020 XLE.

Since I got this Rav in November (2019), there has been a soft buzzing sound (sometimes clicking) coming from the very back of the vehicle when the engine was turned off. This buzzing would occur for all the time the vehicle was off. While none of my previous Ravs made this sound, and neither did my wife's Rav4 (also a 2020 XLE), I did not concern my self too much with it, as it did not seem to affect vehicle function. I decided to wait until my first service visit to get Toyota to look into it.

The vehicle worked fine until the Saturday it was scheduled to go in for its six month maintenance. On that morning, when I went to drive it in, the vehicle failed to start (the engine not turning over, dash lights flashing), which seemed to indicate a dead battery. I contacted Toyota to tell them I would be late for my appointment, and had roadside assistance pay me a visit to boost the vehicle. Once it was boosted, the vehicle ran fine, and I was able to drive it to Toyota for the six month servicing and to check out the reason for the drained battery. They contacted me later that day to say that the battery was run down and they were charging it up. They had no answers for why this had occurred, but I mentioned the buzzing or clicking sounds it made while off, and they said they would have to have a technician hook it up to computer to diagnose it, but being the weekend when the techs were not working, I would have to schedule another visit during the week.

I took the vehicle home that day (Saturday) and it worked fine as usually, still buzzing when off. The next Monday I booked an appointment (which I had to wait two weeks for) to get the buzzing looked at. The vehicle worked fine for those two weeks.

When I took the Rav in for Toyota to look at the second time, they had it for they day, and then informed me that they could not here any buzzing or clicking and said it was probably the exhaust cooling that I was hearing (having driven vehicles for nearly 40 years, and worked on many during that time, I took offense). When I went to pick up my vehicle, it was outside next to the building. I went around to the back of the vehicle and could still hear the buzzing, although it was hard to hear unless you put your ear close to the back end, as the building's A/C system was making a loud racket. I went in to the service department, got one of the service reps to come out and put his ear to the back to hear the sound. He heard it and bough out a tech to listen as well. They agreed to further investigate and I left the vehicle overnight to examine the issue. The next day after looking into the source of the buzzing, they eventually concluded that it was a faulty ECU that was causing a relay or servo to run on after engine shutoff. Luckily they had one in stock and replaced the defective unit and the buzzing disappeared.

It was a hassle to get them to finally take the buzzing seriously and look into and resolve the issue, but now at least there is no buzzing from the back of the car, and hopefully there will be no more draining of the battery. I apologize for the long winded description, but I thought the details of my issue might help others determine a possible explanation for a drained battery, when nothing else seems to be at fault.

TLDR: Faulty ECU caused relay or servo to run on after vehicle shutoff, eventually draining the battery.
 
1 - 2 of 2 Posts
Top