Lemberg Law is investigating widespread consumer complaints about 12V batteries in the 2023 Toyota bZ4X battery electric vehicle (BEV). Owners report that these batteries drain very quickly, sometimes leaving them stranded. Many are finding they have to have their cars towed to dealerships regularly. Typically, these vehicles don’t fail diagnostic testing. This means that dealers refuse to replace batteries under warranty, claiming there is nothing wrong with them.
Issue Summary
The bZ4X is a pure battery electric vehicle that uses powerful motors to operate. The 12V lead-acid batteries handle the starter motor and basic electrical systems. The main power comes from a high-voltage lithium-ion battery pack. This large battery powers the electric motor(s) and is responsible for the vehicle’s electric range. The problems that owners are reporting relate to the starter batteries.
Complaints to the National Highway Traffic Safety Administration (NHTSA) and comments on Toyota forums and Reddit provide proof that there are serious problems with the 2023 Toyota bZ4X starter batteries. There are multiple reports of these 12V batteries needing to be replaced within days or weeks of purchase because batteries lose capacity or fail if they sit completely discharged for a while. This period varies, as you will see from the complaints and comments below.
Even when dealerships confirm that a battery has been drained, if they cannot find a cause, they refuse to replace the battery. Many complaints state that despite ongoing problems with their batteries draining, dealerships maintain that the batteries pass diagnostic testing.
The automaker puts the onus on owners and dealerships to store and maintain batteries correctly. This appears to provide a loophole that results in frequent refusals to replace non-functioning or faulty batteries.
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Toyota’s Policy on Batteries
A manufacturer communication on file with the NHTSA, T-SB-0032-22 Rev, reminds dealerships what Toyota’s policy is regarding battery warranty. It states:
“TSB: A battery in a stored vehicle is subject to conditions that can reduce its performance and service life. These conditions include storage period, temperature, parasitic drain, and battery load. Because of these factors, battery inspection and maintenance are required in order to ensure proper operation and optimal battery life.
“As a matter of policy, Toyota does not provide battery warranty coverage for discharged and/or failed batteries due to lack of maintenance. It is the dealer’s responsibility to maintain the specified State-Of-Charge (SOC) of the vehicle’s battery while in stock and ensure proper SOC at delivery.
“To eliminate customer service concerns due to an undercharged battery during the first few weeks of ownership, ALL dealers should test the auxiliary (12V) battery and recharge, if necessary, no more than 48 hours before delivery to the customer.”
Owner Experience Overview
If cars sit for any length of time — some owners say weeks while others say only a few days — batteries drain and cars can’t be started. Most complaints indicate that this happens at their homes. However, there are cases where people have parked somewhere to travel by air, for example, and when they returned they were unable to drive home.
Some people have their cars towed to a dealership, though there are reports of tow truck drivers starting cars. Apart from the automaker’s policy on battery warranties (above), there is no official explanation why cars with dead batteries do not fail diagnostic tests. There are also no suggestions from dealerships on how to avoid this from happening — except for what the official Toyota battery policy says.
Some consumer comments suggest that if anything is plugged into vehicle outlets after the car is turned off, they will continue to draw power from the battery. Others say that the phone app may be causing the problem.
Some owners have resorted to using third-party 12V fully-automatic battery chargers in an attempt to maximize battery life and performance. In response to this, another user on BZ Forums states, “This is a very poor design on Toyota’s part. In any other EV the low voltage battery would be topped up by the DC/dc converter. The 12V would only be left to die if the HV battery was depleted too.”
The 2023 bZ4X all-electric car did not start and a message on the dashboard read “Parking brake unavailable.” The brake lights were flashing. The car was towed to the dealer, but no diagnosis or explanation was offered.
#2 May 6, 2024
The same car did not start when it was 80% charged. The headlights flashed for a few seconds. The dashboard displayed the time (7:08 am) and mileage (17,734), and the same message “parking brake unavailable” displayed. This time, the owner called Toyota roadside service. The tow truck driver jump-started the car, and stated, “The car battery was at 4%. It should be a minimum of 12%. It is the battery that starts the car.” So, the owner took the car to the dealer and asked if the battery could be replaced. The service manager said, “Only if the diagnostics warrant it.” At this stage, the service manager stated that the starter battery was charged. But, the dealer was “unable to reproduce what was causing the electrical problem and what was draining the battery.”
#3 May 20, 2024
Early that morning (6:28 am) the “car had a total black-out.” It wouldn’t start and there was no electrical power. The owner called roadside service, and again, the tow truck driver reported that the “battery was less than 4%.” It was towed to the same dealer. The car remained there overnight. But, yet again, they couldn’t find anything wrong. “I asked if the battery that starts the car can be replaced.” He replied, “Only if it fails the diagnostics.”
#4 May 26, 2024
Once again, the car wouldn’t start and “had a complete black-out. No electricity. The car battery was charged at 80% as is customary and in prior events. It is the Memorial Day weekend and service dept hours are limited. The car (is) always parked in (the) garage.”
It appears that the dealership did eventually replace the starter battery, as indicated in a follow-up complaint.
#5 and #6 June 2024
The owner lodged a second complaint (same vehicle ID number) on June 24, 2024. “For the 6th time, the car is without power. It will not start although the starter battery was changed by the dealer on 5/28/24. The EV battery does not show any power. It was bought brand new on 1/1/2023.” That was less than 10 months before the battery problems started.
Forum Discussion
A discussion starter on BZ Forums on January 5, 2024 states:
“In my 8-month-old car, the 12V battery drains once every two weeks, and I have to order a tow truck to start the car for me. I contacted the agent and the vehicle underwent all the existing software upgrades. Although I drive a few kilometers a month, the car drives every day or two. Does anyone have a solution or an idea what to do, because the situation is impossible to order a rescue to drive the car every two weeks.”
One response was that this is “fairly common” in EVs. “Hyundai has been having this problem for years with various models.”
Another member states, “Just had my 2023 BZ4X go in multiple times for a dead battery. For me, it was happening after 3-4 days of no use. Not plugged in, all locked up, and no 3rd party equipment. Turns out their phone app is causing the car’s computer to never shut down and drains the 12V battery dead. No fix in the works so now wondering what the next step will be. Battery tender is not always an option. Kinda wish they had the solar panel the UK model had to keep it topped up.”
A discussion starter in the Toyota Nation Forum states that after being away on vacation for 10 days, the 12V battery was dead. The owner recharged the battery and was using the car, but was concerned about the adverse effects on the battery. “I have 2 (of the) same cars and both have this issue. Looks like I need to have a booster in the car.”
“This is the second time in two weeks I’ve had to jump the car to get it going. What is wrong? Is there a software update that I’m missing? Has there been a recall that I’m missing? I don’t know what I’m doing wrong. I leave the car for three days (and when) I come back to start it and it won’t start.” This owner was able to jump-start the 12V battery under the hood.
Another bZ4X owner who says he is a Toyota service manager explains that a 12V battery can drain quickly if the vehicle is left in “accessory mode.” If not, “it could just be a bad 12V battery.” In this event, the dealer will test the battery. “If it passes both tests then the battery is considered good (at this time) but if the battery fails the dealership will be able to replace (it) under warranty but only if the battery fails the load test. If the battery does not fail the dealership cannot replace the battery so please don’t take any frustrations out on your service advisors.”
In response, another owner states, “I just tested the battery at the dealer and it passed. He said there is nothing he can do. I have to wait until it happens again then I will get it towed where it WILL test bad. They have to have a bad test to replace it.
“What’s disturbing the most is what the service advisor said that it’s “ normal”! He said many cars have so much tech that it drains power. I couldn’t believe that it’s normal for a battery to need a jump after 3 days (of) being parked anywhere!”
What Can You Do?
If your 2023 Toyota bZ4X battery is draining very quickly for no apparent reason, contact Lemberg Law. You can call our Helpline or fill out a contact form and we’ll get back to you. It’s not going to cost you anything, because if we pursue your case in terms of lemon law, Toyota will have to pay the legal bills.
About the Author:
Sergei Lemberg is an attorney focusing on consumer law, class actions related to automotive issues, and personal injury litigation. With nearly two decades of experience, his areas of practice include Lemon Law (vehicle defects), Debt Collection Harassment, TCPA (illegal robocalls and texts), Fair Credit Reporting Act, Overtime claims, Personal Injury cases, and Class Actions.
He has consistently been recognized as the nation's "most active consumer attorney." In 2020, Mr. Lemberg represented Noah Duguid before the United States Supreme Court in the landmark case Duguid v. Facebook. He is also the author of "Defanging Debt Collectors," a guide that empowers consumers to fight back against debt collectors and prevail, as well as "Lemon Law 101: The Laws That Lemon Dealers Don't Want You to Know."
