Parasitic drain

D

dgmorr

New member
Hey guys,

What is normal current draw while the car is parked? I'm on my second battery in about 2 months. I took some readings this morning and with the running board lights on and interior lights switched off I get about 970mA. When the running board lights turn off it drops to about 500mA. Is this about normal?

I'm assuming the alternator is good because after jumping my car, the battery will be ok, but it will drain if I don't use it for 3-5 days.

I do have an aftermarket stereo but no aftermarket amp. It has an aftermarket remote starter/alarm (not sure why the factory alarm was replaced). I haven't had much time to investigate deeper because it is pretty cold here now. I'll start pulling fuses when it warms up a bit more.

I haven't changed or added anything electrical since the stereo about 2 years ago.

Thanks
 
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I have no idea what normal current draw for the car (likely in the FSM electrical section though)

If I had to start somewhere on this, I would investigate the stereo and aftermarket alarm install. This isn't to say all aftermarket products are bad but they're the most likely culprit. Even years later, connections can fail or loosen causing issues.

(I wouldn't assume your alternator is good either, get it tested)
it could be as simple as the replacement battery you first bought was defective and then your alternator failed shortly after install of the second battery... coincidences like this are rare, but they do happen...

Good luck, electrical gremlins are one of the hardest items to troubleshoot.
 
Yeah they are the worst to diagnose. I did have a running board light literally go up in smoke two years ago and I just left the socket hanging there, I'm hoping it's as simple as some sort of salt build up causing the issue....likely not

Anyone know if one of these can tell me which circuit is consuming power? I recently talked myself out of buying one of these toys but now that I have an actual problem to find...

Autel MaxiDAS DS708 Vehicle Diagnostics System
 
Just went out to pull some fuses. The first fuse I pulled in the under-hood box was labelled "short pin". Google brought me to another thread indicating this is a fuse for multiple other fused circuits. What is the amperage rating of this little fuse? It has no numbers on it. I went from 800-900mA to 3mA after pulling this fuse.

Found this in the thread. The diagram doesn't really indicate what is on the short pin circuit.
http://im.toyota-4runner.org/attach...key-off-parasitic-drain-05-help-058-012ps.pdf

http://www.toyota-4runner.org/4th-gen-t4rs/75461-key-off-parasitic-drain-05-help.html
 
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i think the aftermarket alarm remote start is doing most of the drain, the brain and bypass usually is the main culprit.
 
I pulled these 3 fuses but I still get a 300mA draw. When I put the Radio No. 1 fuse back in I get up to 900mA but settles back down to 300mA. Not sure if this is just a red herring
 
riceandpho said:
i think the aftermarket alarm remote start is doing most of the drain, the brain and bypass usually is the main culprit.
Click to expand...

I'll have to find out which circuits these are on. The alarm/remote start was installed by the previous owner. Or if I'm lucky enough I'll find an inline power fuse to the alarm brain. Can this just be disabled by pulling the fuse, or do these have some sort of feature to prevent this bypass?
 
First off, the "Short Pin" is not a fuse it is just a piece of metal that connects a large section of secondary power sources for multiple systems. Its function is to disable all uneeded systems when transporting the vehicle to the dealership, you can still start the vehicle; but usually door locks, windows, clock, ect don't work until its plugged in (we put them in as part of the Pre Delivery Inspection when they get off the trucks.)

Second you should get yourself a DVOM and stop yoinking fuses. You need to realize that in an OBDII vehicle when you turn the key off and put it in your pocket many modules need to enter "Sleep" mode, which takes time. What I recommend doing isthe following:

  • Open the Hood, but close the latch with a screwdriver
  • Open your driver's side & passenger side doors, close the latches with a screw driver and unplug or tape down the door sensors
  • Turn the vehicle off, let it sit about 5-10 minutes and then check the amperage draw on the battery (if you're using your DVOM in line, make sure you do not break the circuit between the negative terminal and negative cable otherwise some systems will "wake up")
  • Now you're ready to start hunting for parasitic draws

There's not real specification from Toyota in terms of what is acceptable, but for the most part anything above about 50mA is typically seen as undesirable/indicator of a parasitic drain. I would refrain from pulling fuses as when you reconnect the circuit it could wake up modules and skew your readings, what I would do instead and this is something that is really awesome to use when you learn it, is the following chart:

View attachment Fuse_Voltage_Drop_Chart_-_Mini_Fuse.pdf
(Power Probe has these charts for free on their website for Standard, Mini, Maxi, and Cartridge style fuses: Fuse Charts Download)

Now use your DVOM and check the mV (millivolt) readings across the tops of the fuses, then use the chart to convert the measurement into mA (milliamps.) Once you've found a suspect fuse that has excessive mA draw I would try and find out what is on that circuit that could be drawing that much current, this is where having a wiring diagram will be critical, but it will help you narrow down where you need to go. :)
 

Attachments

Thanks for the tips. I did something similar overnight and checked it out again this morning after it was untouched. I seem to be getting 300mA draw from ECU-B fuse. Anyone know off hand where this is or what is on it specifically? I'm going through the FSM now to try and find it. So far the only thing I'm noticing from the ECU-B fuse removed is a VSC and TRAC off lights.

I'll probably install a battery cutoff device until I can find the source of my problem, kinda lame but what can you do.
 
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Well after going through the circuit diagrams I noticed I tapped into one of the lines off the ECU-B line for my reverse camera. The spec for the camera was 90mA but I guess being made in china it suddenly decided it wanted 1A. I disconnected it and my current draw at rest is between 30-50mA. Kind of embarrassed, but I forgot I had the rear view camera as I haven't used it since I installed it when I got the truck.
 
Another parastic drain - help requested

I've been viewing these forums for help troubleshooting a parasitic drain issue and they've been very helpful - Thanks to all those who've contributed! I have a 2001 4runner and I didn't know what parasitic drain was until last week when I installed a new battery and it was dead a couple days later. I went back to Sears thinking it was a battery issue and they did the DieHard test and found battery & alternator to be OK.

After some more research and a new multimeter, I found that the there's a 7.5A draw on the battery when everything (including door switches etc.) are off. I isolated the draw to 2 fuses: 1) heated mirrors; and 2) J/B 50A (not sure what this one does).

Sure enough, the heated mirrors on both sides were hot even though everything was off. When I remove the heated mirror fuse, the draw goes down to 2.5 Amps which is still high. After I remove the J/B fuse, it appears to drop down to near normal (~ .001 A).

I've been looking for the wiring diagrams for the these circuits but I haven't had any luck. Does anyone know where they can be found? A couple sites were referenced in earlier threads but they aren't active anymore. Any other suggestions on places to focus for troubleshooting the mirrors or what the J/B 50A fuse does would be much appreciated.
 
You can get the wiring diagrams for a 2007 here: Toyota Factory Service and Repair Manual - 2007 4Runner + Updates
Scroll almost all the way to the bottom for "Electrical Wiring Diagram Manual" and then start with the 10th & 11th down. In fact go all the way to the bottom then up 4 sections.
If you have a 2003 or '04 (maybe '05 as well?) some of the diagrams & colors will be different so be aware of that.

Mirrors: http://4runnerclub.com/i/4r_files/f...wd/07toypdf/ewdsrc/2007/4runner/h/em03m52.pdf
On the 1st page of "power source", you'll see about in the middle of the page the 50 amp J/B branches out to several other circuits.
 
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dgmorr said:
Yeah they are the worst to diagnose. I did have a running board light literally go up in smoke two years ago and I just left the socket hanging there, I'm hoping it's as simple as some sort of salt build up causing the issue....likely not

Anyone know if one of these can tell me which circuit is consuming power? I recently talked myself out of buying one of these toys but now that I have an actual problem to find...

Autel MaxiDAS DS708 Vehicle Diagnostics System
Click to expand...

hello ,dgmorr ，from the greetings of 2017,now i found a fanny tool ...AUTEL DS 808，They claimed ds808 has ds708's face with MS906's function body,hhhhhhhhhhhh i will share my experience after getting it .:lever:
 
dgmorr said:
Hey guys,

What is normal current draw while the car is parked? I'm on my second battery in about 2 months. I took some readings this morning and with the running board lights on and interior lights switched off I get about 970mA. When the running board lights turn off it drops to about 500mA. Is this about normal?

I'm assuming the alternator is good because after jumping my car, the battery will be ok, but it will drain if I don't use it for 3-5 days.

I do have an aftermarket stereo but no aftermarket amp. It has an aftermarket remote starter/alarm (not sure why the factory alarm was replaced). I haven't had much time to investigate deeper because it is pretty cold here now. I'll start pulling fuses when it warms up a bit more.

I haven't changed or added anything electrical since the stereo about 2 years ago.

Thanks
Click to expand...

That is why your battery is draining. This is especially true if you have an alarm with a blue LED. Just powering the blue LED requires 10 times the current of an red LED in the older alarms. I bet if you just disconnect this aftermarket alarm then all problems will be solved. FYI - I installed alarms for 10 years and always had the same problem with people who owned diesel trucks with dual batteries having to jump them after leaving the alarm armed for a week or 2. The new alarms draw a huge amount of current compared to the old units and they could even drain the huge dual batteries on an F-350 if the alarm was left armed for 2 weeks without starting the car.
 
BlackWorksInc said:
First off, the "Short Pin" is not a fuse it is just a piece of metal that connects a large section of secondary power sources for multiple systems. Its function is to disable all uneeded systems when transporting the vehicle to the dealership, you can still start the vehicle; but usually door locks, windows, clock, ect don't work until its plugged in (we put them in as part of the Pre Delivery Inspection when they get off the trucks.)

Second you should get yourself a DVOM and stop yoinking fuses. You need to realize that in an OBDII vehicle when you turn the key off and put it in your pocket many modules need to enter "Sleep" mode, which takes time. What I recommend doing isthe following:

  • Open the Hood, but close the latch with a screwdriver
  • Open your driver's side & passenger side doors, close the latches with a screw driver and unplug or tape down the door sensors
  • Turn the vehicle off, let it sit about 5-10 minutes and then check the amperage draw on the battery (if you're using your DVOM in line, make sure you do not break the circuit between the negative terminal and negative cable otherwise some systems will "wake up")
  • Now you're ready to start hunting for parasitic draws

There's not real specification from Toyota in terms of what is acceptable, but for the most part anything above about 50mA is typically seen as undesirable/indicator of a parasitic drain. I would refrain from pulling fuses as when you reconnect the circuit it could wake up modules and skew your readings, what I would do instead and this is something that is really awesome to use when you learn it, is the following chart:

View attachment 145164
(Power Probe has these charts for free on their website for Standard, Mini, Maxi, and Cartridge style fuses: Fuse Charts Download)

Now use your DVOM and check the mV (millivolt) readings across the tops of the fuses, then use the chart to convert the measurement into mA (milliamps.) Once you've found a suspect fuse that has excessive mA draw I would try and find out what is on that circuit that could be drawing that much current, this is where having a wiring diagram will be critical, but it will help you narrow down where you need to go. :)
Click to expand...

could you pls explain the bolded?. i am not really understanding that particular procedure. helping a pal troubleshoot a parasitic drain on an mdx
 
BlackWorksInc said:
https://www.powerprobe.com/fuse-voltage-drop-charts/

https://vimeo.com/231867105

These two things are probably more helpful than I can explain. :)
Click to expand...
was able to isolate the drain to a 10amp fuse called back up. on
pulling the fuse the 0.5amp drain goes to less than 40ma, but then door locks and other systems stops working, so this isnt a cure, am cluesless on how to proceed further. trying to lay my hands on an mdx 2011 wiring diagram- no luck yet.

would appreciate any help/tips
 
[MENTION=66389]BlackWorksInc[/MENTION]

Referencing post #9 by BlackWorksInc

Comments about using screwdriver to close hood and door latches.

If all doors are closed and hood has been popped and left undisturbed for 10-15 mins, can I forego the business with the screwdrivers? In this case - I and doing a volt. drop test within the fuse box under the hood. Yes - doing the same in fuse box inside the vehicle would require putting door switches to sleep.

Thanks.
 
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I had this issue several years ago. Ended up being the JBL amp located in the right rear inside quarter panel where the subwoofer is located.
The sub was broken as well so it all got yanked out. I have the the details on the thread here on t4r.org

CEH in MD
 
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