[Rebecca B]

Hi Everyone,
Recently my check engine light came on and I got a message on my car stating AWD Malfunction, 2-Wheel drive engaged. When I put a code reader on it, I got a low system voltage code. I just had the battery tested at a parts store and they say my battery is good. Has anyone had this issue. I have a 2020 Rav 4 LE. Could it be the battery sensor causing the issue?
Thanks.

 

[Tazio Nuvolari]

the battery tested at a parts store and they say my battery is good.

Your battery could still be bad. You have a 2020 gas model which has the Clarios Enhanced Flooded Battery (EFB).They go bad in 3 to 5 years and many in this forum have been replacing them recently in the 2019 and 2020s. Have you ever removed those Phillips Head caps on top of your battery to check the electrolyte level? It evaporates! Especially if you live in a hot place (S.Calif, Az, Tex etc.) If the electrolyte level in your battery cells is low and exposes the lead plates they get sulfated and the battery won't hold a charge for long. You could have a dead cell. Unless the parts store did a serious load test, you can't rely on a simple scan of the battery volts.

 

[Tazio Nuvolari]

When I put a code reader on it, I got a low system voltage code.

Have you ever gotten a reading of what resting (engine off) volts your battery has? Should be much more than 12.1V. Anything below 12V your battery is toast. Likewise, what volts is your alternator putting out engine running?--should be (hopefully) at least 13V. 5th gen gas RAV charging volts differ widely depending on the model of Denso alternator and trim level. Some only put out 12.65-13.7v...others (my 2021 XLE AWD) put out 14.2V.

 

[Tazio Nuvolari]

Could it be the battery sensor causing the issue?

If your battery state sensor was malfunctioning you would get a DTC code for it with a good scan tool. It's more likely your 5 year old Clarios EFB is toast.

 

[Rebecca B]

Your battery could still be bad. You have a 2020 gas model which has the Clarios Enhanced Flooded Battery (EFB).They go bad in 3 to 5 years and many in this forum have been replacing them recently in the 2019 and 2020s. Have you ever removed those Phillips Head caps on top of your battery to check the electrolyte level? It evaporates! Especially if you live in a hot place (S.Calif, Az, Tex etc.) If the electrolyte level in your battery cells is low and exposes the lead plates they get sulfated and the battery won't hold a charge for long. You could have a dead cell. Unless the parts store did a serious load test, you can't rely on a simple scan of the battery volts.

Thank you, I am still thinking it is the battery as well. Because when it sits for a while it stutters to start but when I drive it or let it run for 30 to 45 mins it starts right up. And the machine at the parts store just states whether the battery is good or not, it doesn't give the actual voltage. I was living in Florida, so it is a Florida vehicle, and I now live in Southern Georgia, so it definitely gets hot. According to the sticker on the battery, it is only 2 years old. But I have also heard that the EFB batteries don't like a lot of vibration, and I live off a dirt road. Can an EFB battery really go bad in 2 years?

 

[Rebecca B]

Have you ever gotten a reading of what resting (engine off) volts your battery has? Should be much more than 12.1V. Anything below 12V your battery is toast. Likewise, what volts is your alternator putting out engine running?--should be (hopefully) at least 13V. 5th gen gas RAV charging volts differ widely depending on the model of Denso alternator and trim level. Some only put out 12.65-13.7v...others (my 2021 XLE AWD) put out 14.2V.

My husband has a multimeter in his tool box. I might try and put that on it to see what voltage it states it has after it sits for awhile, as it has it's most trouble starting. To see what the resting volts are on the battery.

 

[Tazio Nuvolari]

Can an EFB battery really go bad in 2 years?

Yes they can. It may have been defective at the time of manufacturing. It may have always been low on electrolyte. You never know. I'd just replace it. Get an AGM. The Walmart Platinum AGM has a decent reputation and is cheap and has a decent warranty. Be SURE to get the H6 size --not the smaller H5.

 

[Tazio Nuvolari]

My husband has a multimeter in his tool box. I might try and put that on it to see what voltage it states it has after it sits for awhile, as it has it's most trouble starting. To see what the resting volts are on the battery.

Check the resting (engine off) battery volts after the RAV has sat overnight before running it. If you run the engine the battery gets a higher, artificial transient charge. Here are a couple charts showing the proper battery volts. Consider buying a cheap plug in volt meter.Also there is a built in diagnostic function in your 2020 touchscreen that can display battery volts.

 

[Skinny guy]

Bad battery normally doesn't trigger the "check engine" light. Try to scan your car with an advanced code reader.

 

[Rebecca B]

Bad battery normally doesn't trigger the "check engine" light. Try to scan your car with an advanced code reader.

The code is for low system voltage. Which when I looked it up It throws that code when the pcm isn't receiving the correct amount of voltage, so one of the causes is a battery going bad. I just posted on here to see if anyone else had suggestions or the same issue before. Trying everything before having to take to the shop for a big bill

 

[Skinny guy]

The code is for low system voltage.

Do you remember the DTC number?

 

[MilesToGo]

Something to consider: a weak battery will add to the work that your alternator must do (to try and charge battery). It is likely to stress your alternator ( and starter) more than a good battery, since battery not accepting and holding it's charge. Original (factory) battery dies at 2 yrs, on mine. Next crappy battery died in another 2 yrs. So like the old Fram ad "pay now, or pay (more) later". As mentioned, have battery properly load tested, and proceed from there.

 

[iowagold]

When I put a code reader on it, I got a low system voltage code.

Have you ever gotten a reading of what resting (engine off) volts your battery has? Should be much more than 12.1V. Anything below 12V your battery is toast. Likewise, what volts is your alternator putting out engine running?--should be (hopefully) at least 13V. 5th gen gas RAV charging volts differ widely depending on the model of Denso alternator and trim level. Some only put out 12.65-13.7v...others (my 2021 XLE AWD) put out 14.2V.

I like to see 12.5 to 12.7 or more on a sitting battery.
And these newer batteries like a higher charge voltage…
13.5 as a minimum and 14.2 as a normal charge voltage on the newer ravs.

I agree a good volt meter is handy to have
I went the aftermarket usb charge port with battery voltage and when plugged in to the phone it shows the cell phone charge rate.
Less than 25 bucks on that device
And fits the accy switch blanks on the 4.1, and another model for the new ravs with the smaller switches