Chronic battery drain-Help!

Harbor Freight is good source for inexpensive (OK, cheap) multi-meters. Mine also stocks some clamp style meters.

You may be able to rent these items from your local Autozone, NAPA, O'Reilly's or other auto parts stores.

 

I would go on Amazon and get a good cheap multimeter. I have a snap on from my time as a automotive tech. The best is a fluke 87. In my truck I keep a cheap but very effective amazon one made by Tacklife which is no longer available. There are similar ones for around $20-$30 which will be sufficient.

$38 KAIWEETS Digital Multimeter TRMS 6000 Counts Voltmeter Auto-Ranging Fast Accurately Measures Voltage Current Amp Resistance Diodes Continuity Duty-Cycle Capacitance Temperature for Automotive

https://www.amazon.com/KAIWEETS-Multimeter-Resistance-Capacitance-Temperature/dp/B07SHLS639?crid=1M4WI5M1VJD1Z&keywords=tacklife+multimeter&qid=1676469460&sprefix=Tacklife%2Caps%2C168&sr=8-9
Learn how to use one and you will be able to save yourself ALOT of money in electrical diagnostic time.

Test leads I am referring to in the description below:

$20 OCM - 3 Wire Retracteable Test Leads - 18 Gauge Electrical Copper Wire, Alligator Clips, Impact Resistant Case

OCM - 3 Wire Retracteable Test Leads - 18 Gauge Electrical Copper Wire, Alligator Clips, Impact Resistant Case (amazon.com)

Learn how to use one and you will be able to save yourself ALOT of money in electrical diagnostic time.

As for your draw, remember if you diagnose electrical current that the fuse in a multimeter is limited, around 10A. It is very easy to blow these fuses. When you hook up a multimeter in line you will want to connect in through the ground side not the positive side. I do so by disconnecting the ground terminal with a jumper lead to the chassis. With all but the driver's door and hood open and all the other doors closed, close the latch on the driver's door with a small screwdriver while the door stays open (Don't forget later to pull the release to open the latch before closing the door after diagnosis). If the hood has a sensor, most do, then you will need to use either a screwdriver or a large hose pick to latch the hood latch leaving the hood open (again, don't forget to pull the hood release to open the latch after diagnosis), arm the vehicle, with the jumper lead it should still be able to arm the vehicle. Set the multimeter to read amps either through mA or through the 10A. I then connect my multimeter with alligator clamps to the battery ground and to the chassis. All while the power is off to the vehicle. Remove the jumper to the chassis so only the multimeter is connected. mA or milliamp is most likely where you will see your power draw the best. You should now see how many amps the vehicle is drawing; with time you should see all the modules go to sleep except a few small things like vehicle monitoring while it is armed (This should happen in about 15 min). If you are getting a large amp draw, then start working your way through fuses pulling one at a time to see if the amp draw goes down, if there is no change then reinstall the fuse. You can start inside to see if there is a short. Make sure to watch/write down what the readings are between each fuse, and which fuse you pull when the amps go down. This will help trace the source of your draw. If there is no change inside, then go to the engine bay fuse box and repeat the same steps. If you see a large drop in amps now you can find the wiring diagram for that circuit and trace down the source of the draw.

This is a procedure I have followed over the course of 18 years as a automotive technician, it was taught to me at VW and Audi and is applicable to most any vehicle.

 

DOH! I overlooked that my note about this does not apply to 3rd Gen Tacos. Only 1st and 2nd gens, 2015 and older, lose their fuel trims upon extended battery disconnection. Apologies for the error, my bad.

 

Do yourself a big favor and get a test light. Disconnect the negative side of the battery and connect the test light up to the disconnected lead and the battery. Since you have a parasitic drain the test light will light up. Now remove a fuse and see if the light goes out if it doesn't then replace that fuse. Repeat this until you find the circuit because when you do the light will go out.
At least you will know what circuit has the drain. What you are looking for is called a short and a short is an unintended path of electricity to back to the negative side of the battery (ground).

 

also just to rule things out, you could have a local battery store test your new battery,,,, actually do a load test. You could have replaced a bad battery with a bad battery. We tend to assume new parts are good parts, but there is no rule that says we can't get a bad one every now and then.

 

I personally have not used a test light in over 15 years. Mostly because alot of control modules (which could be part of the parasitic drain issue) are solid state. You can damage circuits with unintended voltage.

 

Do you have the feature to remote start the truck with a phone app? I've heard these draining the battery when in areas that gets bad signal.

 

Yes they have their uses indeed. So do multimeters called DVOMs they have their uses as well. I describe to the OP how to use a test light to check for a battery drain within a circuit. I did this because you can use a test light without knowing how to use a militmeter (DVOM).
You can further troubleshoot a battery drain when the multimeter is set on current while placing the leads in series at the negative side of the battery.

 

You want your parasitic draw to be around 35-55milliamp. Get a multimeter with aliigator clips for both leads. Connect it to battery negative cable. And unplug the negative cable. And watch the multimeter while pulling fuses.
When checking interior fuses
Remember to reconnect the negative cable and depress the door switch. The little nub that turns on/off the interior light.


Seems like an ecu is not going to sleep

 

They will do it when the signal is great as well.

 

Thanks, never heard of such.
https://www.ebay.com/itm/195473988657

 

our 3rd gen trucks have lots of drains on them, driving them daily is not enough to fully restore a battery's charge to full. we have smart keys, and handles that are constantly sending signal, and listening for signal, the evap pump running when the truck is off, toyota monitoring the trucks air pressures, distance traveled for service items, security, and more.

even if you drive daily you should put the truck on a charger (a new battery charger not a 70's battery charger) and leave it on until full, every 6-8 weeks. if not, it will be in a constant state of low, and when a big heat swing, or big cold swing comes, you will find the battery to be too low to start and you are stranded, without a jump box (which is also recommended to have, and carry, fully charged).

even if you put a new battery in, it could be bad, make sure it is fully charged, not just guess, it is. and make sure, it can pass a load test. Ski

 

For reference my 2020 drops to 16mA 20 min after key off, same time the center display with mileage turns off.

 

I disagree- I think if you drive daily you'll be fine. No issues with mine, and it sits outside in the cold. Lately, I've been leaving the OBD2 reader plugged in full time as well.

But your results may vary.

And I am fairly paranoid about batteries- my motorcycles and my quad are kept on battery tenders when not in use.

 

so (too many imo) dealers are automatically adding remote tracking/security devices to new vehicles (think lojack for recognized brand). These devices are always on and do periodically connect to a mobile network to get/send updates. If you aren't having luck at dealers, see if there is a reputable auto sound/security shop to track down the draw.

 

Pulling up an old post because I’m having a similar battery issue. Installed an N2 aftermarket remote starter when I bought the Tacoma new. A year and half later needed a new battery. Another year and a half later and my battery is dying very quickly. Is there any remedy for this, other than removing the remote start?? Thanks!

 

A parasitic draw is typically very low amperage, so that it might not even illuminate a test light. I would not use this technique either.

It is not a short either that is the issue here. Some component - e.g., an alarm or a remote start device - is continuously drawing current even when the car is off and draining the battery.

 

Here's one for ya.
Got a letter from Subaru yesterday regarding a possible issue with On-Star ( or whatever the fk it is ) ...

Seems it wouldn't really connect up but kept trying because it was a 3g app trying to connect to a 5g service.
It would keep trying over and over ( constantly ) such that it would eat batteries over time.

I don't use such stuff so it doesn't apply to me, but something to think about.

I know that my garage-door-opening phone app quit working when we moved to 5g wireless....
The garage door opener can't support anything except 3g.

 

Did you ever find out what was drawing the battery down? I’m having the same problem with my 21.

 

Sorry, in true TW fashion, the OP never returned, hasn’t logged in here since October of 2023. It would be nice if people would follow up.
Start simple; unplug each and every aftermarket doodad if you have them,,, right down to phone chargers etc.
GL