Parasitic Draw - '05 GS300

ThinlaneT · November 13, 2020

Hello,

Since Corona-times, my '05 3rd gen GS300 President doesn't get much miles anymore, working almost only from home. I encouraged myself to just drive at least a trip of 30 miles every 1 or two weeks with some highway miles to charge the Battery. Sadly there was a parasitic (unknown) draw going on, which killed my 2,5 year-ish Toyota Battery in June this year, probably when trying to start and the Battery % was eventually almost too low.

I bought a 80Ah Tokohama Asia Battery and worked fine. As the draw from this Battery was also noticable (after two weeks the Battery was flat) I went searching for the parasitic draw. Unhooked the minus-pole and put the multi-meter in serial, I measured a 0.9A draw short after closing the car, 0,37A draw the first 5 minutes after that a 0.17A draw. I also checked after half hour, hour and two hours, but it remained 0.17A. I tried pulling the fuses one time after eachother, but no effect. After being cramped in both footwells and baggage compartment for the fuses, I might have missed one, but I didn't found the fuse that may drop the expected/normal 0.05A draw.

For now I don't have a clue. I removed all the aftermarket stuff (Stinger from previous owner and OBD2 BT device (which I was lost), but no effect. I found in the other fora (as well the IS250 one as I guess they share some electronics), that the MB-X circuit fuse might a source for a draw, together with the Claxon/horn (back-up battery) and also the steering column (when somehow miss-alligned the motor want to reposition, allthough I can't hear any motor or movement). I will check the fuses again. One thing that was interesting, was that when pulling the fuse of DC Cut when in the 0.37A draw moment, the draw dropped to 0.17 inmediately. I found that the method of pulling fuses is somehow questionable as other circuits may takeover the function so a draw like this will be terrible/impossible to find.

Do you have suggestions where to find any draw from experiences in the past?

Herbie · November 13, 2020

Your technique is slightly wrong.

1 hour ago, ThinlaneT said:

I found that the method of pulling fuses is somehow questionable as other circuits may takeover the function so a draw like this will be terrible/impossible to find.

That is your problem.

The only thing you really need to disconnect is the ultrasonic movement sensor in the cabin if your alarm has one so that it can't detect you moving around and trigger the alarm.

You need to open the doors so that you have access to anywhere you need, but you have to fool the car into thinking all doors are closed, locked, and alarm activated. On some cars you can do this by using a screwdriver to flip the lock mechanism to 'Locked'. Oh, and you also need to do whatever is necessary to switch off the internal courtesy lights too - if it's a pin switch, just put some tape over it so that the car thinks the door is closed.

You then need to leave the car alone for at least an hour, two if possible, so that all systems that can and should go to sleep, will do.

Crucially, this is where you should never pull fuses because you can and will wake up circuits and therefore you will not get true readings.

There are plenty of vodeos on YouTube but the one below is a particular favourite of mine. It may be that you don't have the same fuses (the ones with the test points) in which case I would invest in changing them all over to that type. It may be a bit of a pain and expense, but well worth it in the long run.

ThinlaneT · November 13, 2020

39 minutes ago, Herbie said:

Your technique is slightly wrong.

That is your problem.

The only thing you really need to disconnect is the ultrasonic movement sensor in the cabin if your alarm has one so that it can't detect you moving around and trigger the alarm.

You need to open the doors so that you have access to anywhere you need, but you have to fool the car into thinking all doors are closed, locked, and alarm activated. On some cars you can do this by using a screwdriver to flip the lock mechanism to 'Locked'. Oh, and you also need to do whatever is necessary to switch off the internal courtesy lights too - if it's a pin switch, just put some tape over it so that the car thinks the door is closed.

You then need to leave the car alone for at least an hour, two if possible, so that all systems that can and should go to sleep, will do.

Crucially, this is where you should never pull fuses because you can and will wake up circuits and therefore you will not get true readings.

There are plenty of vodeos on YouTube but the one below is a particular favourite of mine. It may be that you don't have the same fuses (the ones with the test points) in which case I would invest in changing them all over to that type. It may be a bit of a pain and expense, but well worth it in the long run.

Thank you Herbie, I'll check how I can disconnect the interior radar. Altough when fully locked, I expected the alarm go off when it was active and I was in. Fore the doors, I pushed the pin-switch mechanism with some clambs tot mimic closed doors. Internal lights go off when performing that (as well as the light on the dash). I also put the key-fob away not to trick the proximity sensor for the key. For the rest, I doubt it matters if you lock or unlock the car. When locking, well some systems go to sleep, but also actives alarm and interior radar and so on. Therefor I checked first without locking, I also locked it and tested again. No difference.

I think the problem here is that I can't find the location of the draw, but I think I can concluded there is a draw afterall. I find it hard to believe that the draw can't be spotted after let say 30 minutes. But maybe I'm thinking a bit simplistic here. I didn't start the car before though, It's just standing there for a couple of weeks now, putting a charger on it, once a week.

Maybe I'll need to spent some on the fuses with test-points and even more patience. As there are 5 fuse boxes, you don't know exactly if all measures are done to mimic all the systems and taking two hours waiting (and start over again if something is interrupted) it's a pretty "draining" job...

cruisermark · November 13, 2020

Could it be the keyless entry? or and aftermarket phone

ThinlaneT · November 13, 2020

38 minutes ago, cruisermark said:

Could it be the keyless entry? or and aftermarket phone

I ditched all the after market stuff (I use the Bluetooth phone thing integrated in the radio/satnav unit) and I put the key away (more than 15 feet). Proximity of the keyless entry is only 5 feet around the drivers door/passenger door

Herbie · November 13, 2020

There should be some datasheet somewhere (although I've never found one for my car) that tells you what current draw is acceptable under normal circumstances. Things like the alarm, the clock, radio presets and so on are designed to be active when other things are asleep and I think I remember reading somewhere that a modern car with all its electronics will have a quiescent draw of about 50 to 70mA, although even that could be classed as high for some cars.

However, if it getting much above 70mA then most likely there's a fault somewhere and this is where patience and testing comes to the fore.

Quote

For the rest, I doubt it matters if you lock or unlock the car. When locking, well some systems go to sleep, but also actives alarm and interior radar and so on. Therefor I checked first without locking, I also locked it and tested again. No difference.

The car needs to be locked because that, as you say, activates the alarm and will therefore draw some current however small, and you need to know what that is for an accurate reading.

ThinlaneT · November 13, 2020

Ok, I’ll have a go tomorrow. One other thing that came up that I have a P0138 fault code, which is the 2nd bank lambda, only occurs after it had rained or it is moist (like a autumn morning). During periods of fairly clear weather, the fault code dissapears. Maybe the harnas of the sensor(wire) has been damaged were humidity effects the faultyness. I suppose that’s only engaged when the engine is on so no draw there.

I might also check the alternator for it’s diode. Its still the original alternator I believe.

ThinlaneT · March 15, 2021

Well, I reached for some help in this quest. Late December I had bought a Battery Monitor 2 of VPM to monitor the voltage on the Battery via Bluetooth and an app. Monitor itself registers each 2 minutes the voltage level, using 1mA. The voltage drop was still significant after the car being recharged (via charger or driving around for 45 minutes, highway mainly). As I've probably try to start the car in the past when the Battery was too low, I may have damage the Battery so I decided to replace the Battery with an new one (Optifit Toyota OEM). I charged the Battery before replacing it with the old one. Sadly after keeping up the same weekly activity of driving around for 35 miles or putting it on the charger, I noticed no difference in the voltage drop by the Battery monitor as with the old Battery. It dies slowly within approx 2-3 weeks (but I don't let it come that far as it damages the battery). Looking at the daily graph the degradation isn't a solid/fluid line, but got some drops in it, telling me that there is still some activity going on.

When putting the multimeter in series, I measured 1.2A after locking, after 1 minute 900mA, after another minute 375mA, followed by 175mA after another minute and keeping up 1 hour and 4 minutes till going to 65mA. I found a fellow '08 GS300 owner which had the same pattern, but experience that the 175mA to 60mA drop was only taking a few minutes. He is using a dashcam (which goes into stand-by) where I don't have any additional/aftermarket stuff. He didn't have that "crusty" line in his voltage degradation (he's using the same monitor as mine).

Pulling the following known problametic fuses didn't effected the score:

- Radio fuses (3)

- Tilt & Telescope Steeringwheel fuse

- Cigarette lighter fuse

- FR and RR doorfuses ( as I noticed that the door didn't unlock once or twice)

So bottomline, I'm stilling having that anoying draw, caused by 1 hour of 115mA above "normal" drain and some activities after an hour. I was also thinking about some can-bus issue, as I am thinking that the GS draining more after a drive than once put the multimeter in series (and therefor need to cut the circuit). It's not based on hard evidence, just the output of the clamp-amp meter (although I doubt the proper reading of it).

Superduner · March 15, 2021

So far this is only a theory - I haven't had the chance to test it out, and may only be valid for my car.

The rubber cover on the tailgate is badly deteriorated and I cannot open the gate "by hand". The rubber is completely solid. I've ordered a replacement rubber, which should be here by the end of the week. Judging by the number of similar rubber parts on eBay, it's not at all uncommon.

I'm wondering if the switch under the rubber is slightly contacting all the time due to the distorted cover and causing a parasitic draw.

Now I'll stand by to be shot down in flames......

ThinlaneT · March 16, 2021

11 hours ago, Superduner said:

So far this is only a theory - I haven't had the chance to test it out, and may only be valid for my car.

The rubber cover on the tailgate is badly deteriorated and I cannot open the gate "by hand". The rubber is completely solid. I've ordered a replacement rubber, which should be here by the end of the week. Judging by the number of similar rubber parts on EBay, it's not at all uncommon.

I'm wondering if the switch under the rubber is slightly contacting all the time due to the distorted cover and causing a parasitic draw.

Now I'll stand by to be shot down in flames......

That's an interesting thing which reminds me the lock unlocks itself multiple times when I press the button (rubber cover) and pull the trunklit open. I think it never unlocks itself once, just 3 or 4 times. Does that sound familiar? I was already looking for the tailgate lock fuse, but didn't found any.

Superduner · March 16, 2021

Mine does not unlock at all using the manual button. I have to use the power button on the fob.

The rubber is rock hard and impossible to "push"

ThinlaneT · March 16, 2021

I pulled the fuse (found it, although some information said also the fuse for the filler-cap controls the tailgate). It won't open now so I suggest it excluded. My rubber is still soft.

Lets find out if it reduces the drain.

Mihanicos · March 17, 2021

Once you have established which fuse draws current, you need the car's circuit diagram to sectionalise the circuit in order to locate the fault. Toyota/ Lexus circuit diagrams include all the circuit connectors and their location in the car.

Any Battery has a nominal capacity in Ampere hours. Theoretically a Battery will go flat when the product of the the current times the time of the current outflow [ in hours ], equals the charge level of the said Battery. Your car may have a 60 Ampere hour battery when fully charged.

Check that the alternator and the rectifier are in good order. Also check the Battery condition.

Chris.

ThinlaneT · March 17, 2021

Thanks @Mihanicos.

The Battery is new since January this year. Didn't start the car when it was below 12.35 Volts and if not driven I put it on the charger weekly (also due to the cold weather this February). Alternator and rectifier are working in good order. Tested the drain on it in October; no drain on that part. Even tested AC voltage over the Battery (as a bad Alternator will have some current running back). Alternator charges (14.2V at cold start, later 13.9/13.8V when "warm").

I have a 70amp/hour Battery. To my knowledge the practical capacity of a fully charged Battery is 70% (as on less than 30% of the Battery the motor probably won't crank and it definetly will damage the Battery if you do so) * 70Ah = 49Ah -> 49 / 65mAh = 754 hours = 31 days till the Battery should be "dead".

As I notice some voltage drops on those 2 minute intervals my monitor registers; the average drain is probably a lot higher. I noticed on the Amp meter some peak drain of 300mA for a couple of seconds, but without a proper scope I can't have a say on the actual average drain. As I follow the trend my Battery is dead within 15/16 days so the actual drain would probably around 130mAh.

Mihanicos · March 17, 2021

When did the car develop this fault? Has it had any accident repair, minor or major afterwards? Has it had any maintenance or repair about that time? Check where mechanics and body panel workers have been. Most of them leave their mark behind. Check for harness and cable damage, short circuits to ground or between individual wires.

Follow the voltage drop method accross the fuses, put forward by another learned member. For circuit diagrams you can get from Lexus-tech.eu or from other repair manuals on eBay. You can print anything within the time you have bought access for, it is about 5 Euro an hour if my memory serves me right.

Finding faults like your car's is a very tedious and time consuming process. You need patience and perseverance. I will be very happy to help in any way I can.

Chris.

ThinlaneT · March 17, 2021

Since I bought the car (October 2017) it probably already had the issue (seller didn't tell me about it), but experienced no signs of it as I drove at least 2x 50 miles, 4 times a week, keeping the Battery fit enough. I once left the trunk open over a night during a cold winter night. Although I think the GS shuts the tailgate light after 15 or 30 minutes, the Battery was dead enough to only trigger the starting relais, somehow. Soon after that cold winter the Battery finally died in march 2018, 2,5 years old. As the car came from the east-side of the Netherlands, which have colder winters than where I live, mixed by the fact the previous owner only drove short trips with it, the Battery was probably already passing away for a while.

I checked most of the cables by eye for damage but couldn't see anything in kind of damage or wear. The only thing is, when the dampers of the tailgate were a bit old and loose, some friends slammed the tailgate pretty hard, forgot that I said it had auto/soft-close... That's why I'm guessing the tailgate lock as cause of the drain, as it since then, unlocks itself 4 or 5 times when opening the boot by the button on the boot.

No damaged occured when I got the car. Still driving lovely, once it drives... Checked the ground-cable from the Battery to the chassis (which sometimes get rusty as it is in a quite humid and dirty environoment), but is was nice and clean.