Chronic battery drain-Help!

My 2019 Tacoma TRD Off-road 18,500 miles has had a battery drain issue for 2 mths. Battery checked @ local auto store & said it was fine. Contd to have to jump start after it would sit for only a day. Battery replaced with no change. 2 entire days @ local Toyota dealer & they cannot figure it out. Warranty expired 6 mths ago. Please help! Costs accruing with no result @ dealer & desperately need vehicle for my hospital job-have no other transport/concerned about getting raked over because of being a chick. What do u do if dealer cannot remedy after warranty???

 

Do you have any aftermarket stuff wired into the truck? Lights, stereo, alarm, etc? Dos the alternator test out good?

A cheap stop gap solution to battery drain would be a quick disconnect like in the link below. A bit annoying to have to do but it will keep the battery from dying while you figure out the cause.

$9 AUTOMAJOR Quick Battery Disconnect Switch Top Post With Anti-Corrosion Washers - Battery Isolator for Car, Truck, Marine, RV and Electrical Equipment - 12V/125A Reliable Cut/Shut Off

https://www.amazon.com/Battery-Disconnect-Switch-Corrosion-Washers/dp/B09L73JK5P

 

If the dealer could not find the parasitic drain, they are either incompetent or skimming you because you are female.....
If you have access to another dealer, I'd say take it elsewhere. When it gets found and fixed, bill the original dealer either for the repair or the cost incurred by the first dealers inability to repair it. Whichever is greater.

With that said, do you have any aftermarket accessories installed? A parasitic drain is not hard to trace as they can access the computers to know which one is not shutting down or use a DMM to find the particular circuit.

 

Was anything newly installed within the last two months?

Idk what your local Toyota did - but I can share what I’ve done in the past.
My 08 G35 had a battery drain similar to yours. I added no new electronics (no new alarm, radio receiver, etc.) upon the time it started to act up.
I took a multi-meter to EVERY, SINGLE fuse with the key out and vehicle off. I found the fuse that’s for my factory radio was running power somehow.
I googled it and it was a common issue for the Infiniti’s rear disc changer to have a draw. I removed it and never had a problem after that.

If you have a multimeter or don’t, borrow from a friend or buy one and try that out. Literally check every fuse to pinpoint roughly where the draw is coming from. Then you can begin a thorough search

 

Find a multimeter that can measure current, either a clamp on style or one with leads and measure the current being drawn from the battery about 15 minutes after you turn the truck off. A clamp on will not be as easy to find, but will be easier to use. If you have one with leads you'll want to disconnect the negative cable and use the meter to complete the circuit.

Then start pulling fuses one at a time until the current goes away. That will tell you what is causing the load so you know where to look.

 

Welcome to the forum sorry this has to be your first post.

2 days at the dealer and they can't figure it out -- you need to try a different dealer.

 

First one I would check for parasitic drain would actually be the alternator.

 

Junction Block Ecu.

 

Thank u for responses. I have zero aftermarket applications. I figured that alternator would be their 1st check prior to electronics/wiring?? I researched security system malfunction too because red light was staying on solid when locked. Doesn't it flash when engaged/locked ??Next move will be another dealer. Off Wed so I can actually discuss w/ them in person. I regret that this is my welcome post. I did love my truck.

 

That’s a start, no aftermarket doodads. Are you sure the alarm wasn’t an aftermarket the dealer installed? If so, I’d start there,,, aside from another shop.
These electrical gremlins can be tough, you need a good tech to go through systematically.
GL

 

I don't believe it was dealer installed security system. I read that some Tacomas prior to mine could be reset with manual key turning 5x quickly, but mine is keyless. Technology is overrated.

 

EDIT: OOPS, WHAT I WROTE BELOW ONLY APPLIES TO 1st and 2nd gen Tacos, 2015 and older. NOT 3rd gens.!!!

If you use a battery disconnect, keep in mind that your truck may run rough and/or idle much higher than normal, and do random-seeming, spontaneous idle-rpm changes (unexpected spontaneous revving) when the truck is in Neutral or Park with the engine running. This is because the ECU (engine computer) forgets its fuel trims (learned & stored fuel-air ratio calibrations) when it is disconnected from battery for longer than 10-15 minutes.

Whenever the ECU is cleared of fuel trims (by power loss, typically,) upon next start-up it will go through a series of somewhat-involved engine routines to re-learn the fuel trims. Typically this takes somewhere between 100 and 400 miles, depending on your driving patterns and habits.

If you are disconnecting the battery frequently or after every drive, the ECU will be starting from scratch to learn fuel trims over & over, hence your engine may seem to be "running strange" during all that time. Gas mileage may also be seriously impacted.

When battery drain issue is fixed & your batt. goes back to being connected all the time, the ECU will re-learn fuel trims a final time & eventually the engine should start to run completely normally again. (Assuming there are no other pre-existing issues with it.)

 

This is probably the most expedient & direct method to start tracking down the problem. Take care pulling the fuses not to crack them, it can be difficult as they are usually tightly seated in their sockets. A cheap

$7 QWORK Relay Puller Plier, 9-1/16" Long 3-3/4" Maximum Opening Auto Metal Relay and Fuse Remover Tool

fuse-pulling pliers may be helpful. $8 on Amazo n. (I picked one of these up recently.)

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By note of comparison, I just went & checked the DC current draw on my own 2014 Tacoma battery. Using a Fluke® 323 clamp-on meter around the positive battery lead (actually there are two main positive leads on my truck, so putting the clamp around both cables at once) I read 0.00 amps with key out & the truck at-rest for several hours. (It takes a certain amt of time after removing the ignition key & exiting the vehicle for the on-board computer to "go to sleep" & reduce its current drain to very, very low levels. )

Open driver's side door: 0.04 amps, steady, no dome light on (ECU waking up.)
Turn on LED aftermarket dome-light: +0.02 amps, for +0.06 amps total.
Headlights on: +1.21 amps, for +1.29 amps total.

0.01 amp is at the bottom end of this clamp's measurement range, but since it's a Fluke®, I trust even the low-end readings. Inexpensive off-brand DC clamp-meters may not have much accuracy below 0.10 amp.

 

Wow. Sorry to hear

 

I had this issue on my 2019 TRD OR at one point. My solution ended up being not leaving the alarm armed while it was parked in the garage. This may not be an option for you if you park outside but maybe it will give you a starting point. Mine would be really low after a few days of sitting locked. When not armed, it could go weeks as it was not my daily driver. Good luck with it.

Also to note: I did have the directed (viper) smart start added to my truck. (where you can start from your phone)

 

The security light should be solid red for 30 seconds after locking the doors I believe.

This is false. Disconnecting the battery will not reset or clear any learned values.

 

This is a good test to narrow things down

 

Does it go dead at home, at work or random? How's your parking situation? I have seen a battery die when the owner parked in the garage and then hung the key on a hook just inside the door, less than 5 feet from the car. The key and the car just kept communicating back and forth until the battery died.

Our batteries should be around 80Ah or so- which means the battery will be 50% drained (and likely unable to start the vehicle) in just 3 days with a 0.5A current draw, it takes surprisingly little.

 

There’s a thing called a Priority Start. Sold on Amazon, amongst other places. Automatically disconnects battery before it goes dead, re engages with a load applied such as headlights. That doesn’t help with the troubleshooting but it will keep you from getting stuck somewhere.

 

You have 2 choices,

1. take it to an independent shop and pay out of pocket
2. get a multi meter and start going through the fuse box and testing the draw of each circuit. Make note of the circuits that have significant pull.