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2017 Rav4 Hybrid Limited - parasitic power drain

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tantalumoxide

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Discussion starter · #1 ·
Hi all, as the thread title suggests, I have a 2017 Rav4 Hybrid Limited edition that seems to be experiencing parasitic power drain that is killing my battery.

Background: in the last few weeks my battery has died if the Rav has sat for more than a couple of days. I've boosted it, it seems to charge while driving as it will be good, no power issues unless it sits again for a few days.

Thought it was the battery as it's about that age, but I took it to the local shop to get it checked out and they found that the Rav has a 130-140 milliamp drain on it once everything has shut down. They finally found that, if they pull the 10A fuse for the Steering Lock ECU, the power drain drops to a reasonable, if maybe even low 30 milliamps, so they think that is where the problem lies. There are no warning lights on the dash except when the battery doesn't have enough power to start the engine.

So my question is: has anyone else had this issue and if so, did you find a solution to it?
 
#2 ·
I assume you mean the 12 volt battery, not the high voltage traction battery.

Is this the original OEM battery or has it been changed at some time? Five years is about all most people get out of the OEM 12 volt battery.

The 12 volt battery does not start the gas engine a hybrid. The gas engine in a hybrid is started my MG1 in the "power split device" (transaxle) using the HV battery. But you do have to have enough 12 volt power to run the electronics that control the the hybrid system.

What is the battery voltage when the car has been sitting awhile with the engine off? It should be about 12.6. What is the battery voltage when the car is in ready mode (turned on)? For the hybrid, the system manages the charge level of the 12 volt battery, but it should be between about 13 and 14.5.

Suggest you get your 12 volt battery load tested. Most auto parts stores will test it for free. That should help you decide what path to go to solve your problem.
.
 
Discussion starter · #3 ·
Yes, should have specified that it is my 12V battery that is the issue. I'm not sure if it is the original as we purchased the Rav at 3 years old (2020). But it could be and yes, it's about that age to be replaced anyway if it is.

Didn't know that the 12V battery doesn't actually start the gas engine in the hybrid. So if it doesn't start, it is because the 12V battery doesn't have enough power to run the electronics? The high voltage battery seems to be working with no issues. We had it checked by Toyota last year at this time.

But my bigger concern is the power drain. Is that 130-140 milliamp drain something to worry about, or is it normal for a Rav4 hybrid? I don't want to put a bandage on it by purchasing a new battery and then still have the same issue of power drainage occurring. Everything I've seen indicates between 50 and maybe 90 milliamps is normal "power off" usage.
 
#4 ·
tantalumoxide said:
But my bigger concern is the power drain. Is that 130-140 milliamp drain something to worry about, or is it normal for a Rav4 hybrid? I don't want to put a bandage on it by purchasing a new battery and then still have the same issue of power drainage occurring. Everything I've seen indicates between 50 and maybe 90 milliamps is normal "power off" usage
Click to expand...
Have the 12 volt battery load tested and the voltages measured as I described above.

Original Toyota batteries will have a Toyota label on them.
 
#5 ·
Check your relays. I have a customer that had a parasitic drain issue on a newer vehicle that he bought new. He took it to the dealer about 3 times and they could never find the issue. He was about to give up and get rid of the car. He found it to be a bad relay. He replaced the relay and the issue went away.
 
#7 ·
tantalumoxide said:
Hi all, as the thread title suggests, I have a 2017 Rav4 Hybrid Limited edition that seems to be experiencing parasitic power drain that is killing my battery.

Background: in the last few weeks my battery has died if the Rav has sat for more than a couple of days. I've boosted it, it seems to charge while driving as it will be good, no power issues unless it sits again for a few days.

Thought it was the battery as it's about that age, but I took it to the local shop to get it checked out and they found that the Rav has a 130-140 milliamp drain on it once everything has shut down. They finally found that, if they pull the 10A fuse for the Steering Lock ECU, the power drain drops to a reasonable, if maybe even low 30 milliamps, so they think that is where the problem lies. There are no warning lights on the dash except when the battery doesn't have enough power to start the engine.

So my question is: has anyone else had this issue and if so, did you find a solution to it?
Click to expand...
Knowing already that the 10A Steering lock fuse isolates the parasitic drain should make it easy for the dealership folks to figure out. Just tell them you want an accurate diagnosis not a "parts canon" approach. It has been awhile since you posted this - did you get it figured out?
 
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