Odd battery drain, less drain after doors locked, 06 LX470

[Jacobs]

We just recently purchased a very well maintained LX with 150K on the clock. It has a heavy drain that is intermittent, that I have not found (I think it's the rear DVDs), and another one that I did find that seems odd.

When the truck is complete, all fuses in with an ammeter in the BAT fuse, it pulls ~150 milliamps. When you lock the truck with the key, or lock it and close the door it only pulls 23 milliamps. Very repeatable. Unlock 150, lock 23.

Security system? Immobilizer? Hoping someone knows what might happen when the doors are locked vs. unlocked that might cause this.

I think the security light flashes even when the truck is not locked but I'm not completely sure...

-Jaco

 

[TXLX100]

It's normal. I recommend anyone's car that is going to sit for weeks to lock it, it shuts down more of the on-board systems, when locked. Also, on newer cars with smart fobs, to keep the car locked and keep the key inside the house far away from the vehicle (not hanging in the garage next to the car. When the key is near, the car is constantly reading / searching for it.

 

[SanDiegoCruiser]

I have this exact same issue and have just decided to lock my rig while it’s parked in my garage. I even started a thread on this a couple of weeks ago.

 

[Spike555]

It's normal. I recommend anyone's car that is going to sit for weeks to lock it, it shuts down more of the on-board systems, when locked. Also, on newer cars with smart fobs, to keep the car locked and keep the key inside the house far away from the vehicle (not hanging in the garage next to the car. When the key is near, the car is constantly reading / searching for it.

I know of people who have the smart fobs, stayed at a hotel while traveling, had car in front of hotel room, went to bed, car unlocked because fob was within range, everything was stolen out of the car while they were sleeping.

 

[Jacobs]

Thanks for the replies, I'll have to try with the key further away and see how much the drain is...

I thought the maximum allowed drain according to Toyota was 50 milliamps and I'm getting 150 which is certainly higher than any other car I've messed with. That's just the BAT fuse as well, I think it's pulling more than that when the ammeter is hooked into the entire system.

I know via the records this thing has a history of eating batteries, but if all I have to do is lock it that's fine with us!

 

[Spike555]

Any car with tons of computers is going to eat batteries.

Why did you check this in the first place? Were you having problems or just curious?

 

[Jacobs]

Why did you check this in the first place? Were you having problems or just curious?

We just recently purchased a very well maintained LX with 150K on the clock. It has a heavy drain that is intermittent, that I have not found (I think it's the rear DVDs), and another one that I did find that seems odd.

 

[Jacobs]

So doing some math with the forumulas from here: http://forzacomponenti.com/documents/Parasitic Current Draw_Batteries_Battery Tenders V3.pdf

You can see why Toyota wants the drain to be no more than 50mA... At my ~200 mA with the doors unlocked the battery will not last but maybe 7 days. With them locked at ~75 mA the battery would last about 18 days. Both unacceptable really. At Toyota's max allowable of 50 mA drain the battery would last about 27 days...

 

[KillerBox]

I have read on a post here on mud that if you leave your automatic headlights in the auto position that it will draw more current while shutdown. So switch your auto headlights to the off position and see if that helps your current draw?

 

[Jacobs]

I have read on a post here on mud that if you leave your automatic headlights in the auto position that it will draw more current while shutdown. So switch your auto headlights to the off position and see if that helps your current draw?

I did try both positions, even tried pulling the fuses to the headlights, no avail- thanks for the thought though.

 

[TXLX100]

I did try both positions, even tried pulling the fuses to the headlights, no avail- thanks for the thought though.

Were you able to pull fuses until you found out what system is drawing? 23mA draw when car is locked, seems better than normal to me. Standard flooded batteries aren't designed to sit for days or weeks. Even daily driving them 5 miles is rough on a battery, you'd be lucky to get 2 years on a battery in Texas doing that. If your car is going to sit for a week or more often, I'd recommend a battery tender or put a small solar charger on it that's easily unplugged, or a battery cutoff switch.

 

[Jacobs]

Were you able to pull fuses until you found out what system is drawing? 23mA draw when car is locked, seems better than normal to me.

That's kind of the point of this whole thread is that the drain when locked is ok (granted that's just the BAT fuse. Drain from the whole system locked is 75 mA... should be under 50)

Pulling the dome fuse = 90 mA (unlocked)
Pulling the ecu-b2= 10 mA

Granted ecu-b2 runs the following:


AHC and AVS
AC Front
AC Rear
Automatic Light Control
Center Diff Lock
Comb Meter
Cruise Control
Door Lock and Theft Deterrent
ECT and AT Indicator
Engine Control
Engine Immobilizer System
Front Wiper and Washer
Headlight
Interior Light
Key Reminder
Lexus Nav and Rear View Monitor
Light Auto Turn Off System
Moon Roof
Muyltiplex Comm System
Power Seat
Power Tilt and Power Telescopic
Power Window
Rear Wiper and Washer
Remote Control Mirror
SSeat Belt Warning
VSC
Wireless Door Lock Control

So knowing what happens when the doors are locked would be helpful...

 

[Jacobs]

Here's what I have tried so far. Wife drove the truck to work so anything more will have to be tomorrow...

 

[Spike555]

Sorry, I missed that part.

 

[SanDiegoCruiser]

Have you tried waiting for 30 mins to see how much difference sleep mode makes? In this mode, the dome lights shut off...

 

[Jacobs]

Have you tried waiting for 30 mins to see how much difference sleep mode makes? In this mode, the dome lights shut off...

Yes, even sitting overnight the drain in either condition remains the same.

I posted this because this thing eats batteries, the last Toyota oem battery lasted 3 weeks driving the vehicle regularly. I thought the large drains I listed would make this obvious...

You cannot drain batteries over and over without sulfation/failure. Still we are putting an Odyssey and probably a priority start next, but I still want to solve this problem as we like to go to very remote places.

 

[SanDiegoCruiser]

I have similar readings when I spent 1/2 a day tracking it down. I just decided to lock my doors when I park it. But I too am interested in tracking it down.

 

[luchoboost]

Did you solve the issue? I have the same problem, my battery drain in two days, I tested the drain with a multimeter and a test light and stop when I pull off the SHORT PIN fuse, but I don´t know for what this "FUSE" is for, without this fuse my truck runs, but, runs without radio navigation and show the ligths vsc off and vsc trac on.

 

[Spike555]

Here is a question for you guys with battery drain, is your CD changer cartridge in the unit?

Usually, not always, when a CD changer is heading south it will cycle through all the discs non stop, you know how when you load it it see's whats in there? But it'll do it continually until the cartridge is removed or the battery dies.

 

[luchoboost]

Here is a question for you guys with battery drain, is your CD changer cartridge in the unit?

Usually, not always, when a CD changer is heading south it will cycle through all the discs non stop, you know how when you load it it see's whats in there? But it'll do it continually until the cartridge is removed or the battery dies.

I removed the cartdrige but the drain is not from there..