Parasitic draw (power draw) issue. Help!

So I have been having a pretty heavy Parasitic draw of about 180mA where it should only be ~50mA when the 4R is off. We pulled all aftermarket electronics and when i remove the Short pin fuse under the hood that conserves power when in transport it goes away. Think its the ECM/BCM/ECU (Not sure the terminology) when that fuse is removed it drops to 27mA, as soon as its plugged in jumps back up PTC Heater #1, PTC Heater #2 and 3rd seems to reset it.


Possibly the main body ECU issue that's used for transport? I did have some snow get into my in cabin filter and blower area last year from the vent/cowling (stupid Toyota design).

Going to bring to the dealer but wanted some insight from those who may have had an issue like this or just more experience than my self so i can assist the dealer in narrowing it down.

Luckily I have a AGM deep cycle battery because my 4R would be dead in a matter of days with out it. Such a bummer....

Thoughts?

 

Maybe it's just me, but I'm having trouble understanding this part:

when i remove the Short pin fuse under the hood that conserves power when in transport it goes away. Think its the ECM/BCM/ECU (Not sure the terminology) when that fuse is removed it drops to 27mA, as soon as its plugged in jumps back up PTC Heater #1, PTC Heater #2 and 3rd seems to reset it.


Possibly the main body ECU issue that's used for transport?

 

Fuse # you are pulling might help us help you.

 

Not just you. This is my notes from my local car audio guy i had help me. A little difficult to follow.

Let me see if I can find the fuse we pulled. Supposedly its the one for the Main Body ECU.

 

Nevermind 36?

 

Yes, pretty sure #36 is the fuse.

 

I don't have access to toyota TIS maybe someone here will be nice enough to show you what comes of the ECU so you can look at disconnecting those individually.

I would doubt it would be the whole ecu but never know.

Or you can pay for a short subscription.

https://techinfo.toyota.com

 

What caused you to investigate this, was the battery dying? 180 mA may not be unusual, depending on your electrical loads and when you measure the current.

My 2018 ORP goes through two power consumption scenarios (600mA, 135mA) before it stabilizes at its true quiescent “parasitic” power draw after 20-30 minutes (12mA). Maybe you need to monitor it for longer to get a true reading.

Here’s a description of how I characterized mine, see post #44:
https://www.4runners.com/threads/ma...ck-wont-start-at-all.21042/page-2#post-309640

 

I became aware of the parasitic draw a few months after getting my AGM battery. I had been using it for a few months with no issue but when my commute went from 1hr to 10 min I noticed the battery level dropping overnight more than what I would think. Like 12.7 to 12.3 in 15hrs. That's when I added the voltage booster to help recharge the battery when driving, plus I trickle charge once a week to maintain the batteries capacity.

I did a test when initially turning off the 4R and got ~180mA draw, let it sit for an 1/2 hour with the doors locked and it dropped to 120mA. I also brought it to my car audio place and they tested over 5 hours after removing all the aftermarket stuff and they confirmed the 180mA draw.

Maybe I am making a mountain out of a molehill, but if i let my 4R sit for 5 days the battery would be dead. Never had that with any other car.

 

You’re right, that 120 mA is rather high. You could try checking for an always-on circuit somewhere. Usually lighting or some circuitry you’ve added to a constant 12V source. Also, anything plugged into the OBDII port (Scan Gauge?) will get constant 12V. Try removing all circuits like that to get as close to stock setup as possible and measure again to get to under 50 mA. Then add one circuit at a time to find the culprit.

You may have to pull individual fuses to track it down.

Also check to see if there’s any dealer installed nonsense like a GPS tracker module near your fuse box. Good luck.

 

Well, went to the dealer and gave them all my results and they wanted to check from scratch to be 100% sure of the draw.


Turns out no abnormal draw.......... And after everything went to sleep they measured 67mA....

I guess my AGM just has too much capacity to charge enough on my short commute, and in reality the capacity isn't really that much if 60mA takes 4-5 volts over night.

 

Update!

Went on a short camping trip and in the matter of 31 hours my Compustar remote start warned me my battery was low, actually almost dead. So I started my 4R and it just barely turned over, so i let it idol for about an hour to recharge just to be safe so I wouldn't get a warning again waking me up (I sleep in the 4R). Made it through the night and morning.

Now I am perplexed. I get this AGM battery for extra capacity and it does not make it through the night when my stock non AGM would go for days. Its not like i was running anything big or for very long. Just don't get it......

Maybe when the doors are not locked it does not put the electronics to sleep?

 

Just a thought but maybe your Alt is no good and is only charging sometimes so you are actually draining the battery when driving?

 

Could just be a bad battery. We replaced my son-in-law's battery recently, and it was dead within a few months. Turned out to be bad. The replacement has been fine.

 

Have the battery, alternator and charging system checked by a competent auto electrics shop.

You have a charging and/or battery problem, not a parasitic load issue.

 

Did you ever resolve your high parasitic current draw? Toyota specs 50mA max.

Are you using your AGM battery for anything but a starter battery?
Are you powering any accessories while camping?
Extra lighting, dash camera in parking mode, Scan Gauge or anything else plugged into the OBDII port?

How old is the AGM battery? If you live in a hot climate it’s not unusual for batteries to die in 2-3 years

 

Battery is a brand new AGM (~1yr). Its mostly used as a starter battery but the purpose upgrading was to provide more run time for my interior light set up when I camp. Its really not a lot and I didn't really use much of the lighting on my last trip. Definitely no more than i had in the passed with a regular battery.
I do have Maestro module for my Kenwood head unit connected to the OBDII

Alternator is Definity charging as well. 4R is only 4yrs old.

 

Yes, definitely a charging issue too, but not necessarily because there is something wrong. I only have a 10min commute so the battery rarely gets fully charged so I trickle charge once every week or two and i run a voltage booster. The time it went almost dead it only took an hour at idol to charge the battery up so its definitely getting charged. I have a tester so ill check the charging system.

 

Connecting to the OBDII port supplies constant power to your new Marstro/head unit. That could be your problem.

Check out a similar problem in a Tundra thread:
https://www.tundratalk.net/threads/serious-problems-with-new-head-unit-and-idatalink-maestro.755437/

 

Really good info, thank you. I will stop by my install shop and point this out, and maybe disconnect or make a quick disconnect if this is the culprit. It may be all because of the remote start LTE and OBDII.

 

Figured I will update as my journey goes.

Did some amp draw testing with different doors open and letting the car sit. I can get the amp draw down to .25-.35 mA after a few minutes of sitting with the doors closed. If I open the doors it jumps pretty high to 2.0-3.0 mA+ and will lower if I turn off the interior lights. So to be expected?

I also tested the battery and did a crank test as well as a charging test which was all normal.



So I am left with a random power consumption possibility after it sits for a while (though i cant find it). Like the LTE of the Compustar (though when i connect with the app it doesn't draw much more) or some OBDII port Marstro connection issue that's random after it sits? Just so strange since its not showing a parasitic draw and even 14V is not really charging. (Granted I only have a 20min commute).

I am starting to think the AGM option is not a good way to go since it seemed fine on the stock battery.

 

I'm curious why your Maestro needs an OBD connection. I have one in my '20 for my Pioneer and it does not connect to the OBD port.

 

All the data and the ability to reset codes on my Kenwood DMX head unit (several screens):

 

Yeah, I've got all that too and it does not have an OBD connection. It gets all that info from another harness.







I'd just started it so it was still getting tire psi info.

 

The reason I asked is that - as someone else mentioned - I wonder if the OBD connection has something to do with the problem you are having. Below is a list of what I bought from Crutchfield for my install, and you can see the Maestro (iDatalink) parts in there. Are yours any different? If so I wonder if my parts list would work and you could eliminate that OBD connection.

 

Sounds like a mismatch between the stock alternator and the new battery.

 

Thanks 08tx, that's really good to know there is an alternative connection rather than the OBD since it could be the culprit. Ill have more info to provide my install shop.

 

Its just a recommended AGM option. Though I did question this initially, the voltage booster should compensate for the extra voltage needed and it does charge. It just depletes faster than I would expect from an AGM.

 

I haven't read all the posts, but I will throw in a little thing that might be involved just because I had to deal with it on an earlier version...

The hood latch is tied in with the alarm system. When it's open, it keeps all sorts of modules awake.

Toyota's quick training guide reference QT611B references using a screwdriver to latch the hood alarm sensor into a closed position. I was unable to accomplish that and carefully released the spring and closed the latch while the hood was still open.

A bit of a pain, but it helped me get an accurate parasitic draw level.

By the way I felt that my connected services head unit in my 2020 4Runner was the culprit, after everything went to sleep, it was still drawing 52mA. Still outside of the specification Toyota says is acceptable.

 

Than that's really strange. When I did my over time draw testing in post #21 I left the hood open and was able to get it down to 25-35mA draw.

Seems a few common issues that come up are aftermarket Audio systems and there options. What's strange I did the Audio system first and didn't seem to have any issues with parasitic draw and the stock battery. Only became an issue when I added the AGM battery, Compustar remote start and neglected to put in a Booster for 9mo.