Parasitic Drain Killing Battery
10-07-21, 06:57 AM
#46
Moderator
Salim
The following users liked this post:
Wassum3636 (10-11-21)
10-07-21, 11:57 PM
#48
Driver
Thread Starter
I believe that the modules SHOULD be able to go to sleep regardless of locked or unlocked unless I am missing something (and I may).
Could someone point me to where it addresses that the doors must always be locked when the engine is not running (and the alternator charging, overcoming any minor parasitic draw) I am not "arguing" but trying to learn and will "mend my ways" in teh RX if it's a requirement. It does seem illogical for THIS model car to need to be locked when all of my other cars never needed to be? Is it true of other recent Toyota products? My wife's 2013 RX350 goes months unlocked and unstarted when she is out of state with the grandkids and its battery seems to hold up OK is why I ask.
It would be helpful to have a LONG timebase oscilloscope that could measure battery discharge and display it over long time periods (say 24hr) so that if the drain is intermittent (appearing and disappearing maybe while WE are sleeping but our modules are insomniacs and waking up periodically). We cannot be awake 24/7 staring at a meter to see when a draw may appear or disappear.
Has anyone tried removing fuses and leaving hem unplugged one system at a time for several days? I often do not use my RX for long periods (I have and use several cars), and it would be interesting to establish a pattern for each feed one at a time like this to see when the battery does NOT go flat when a particular fuse has been removed fro days or a week.
10-08-21, 05:48 AM
#49
Driver School Candidate
I haven't bothered to leave the fuses out because the fuses at fault are a large part of the draw. Pull one and its down 30%, pull the other and its down 30% (rufly). I did shut and lock the doors yesterday after plugging things back in,(radio, display, heater,cd-player etc.) came back 1/2 hour later and it was at 38 to 40 ma. I could be wrong but I really think putting in the new diode pack in the alternator helped because even though the alt tested good, I set the body of the alt on the pos post of the battery and got voltage through the cable terminal, then reversed it, terminal on battery test lead to body of alt and got voltage. One thing I havent said here is that it is a replacement alt was a denso and had a 6 diode pack, this new pack has 8 diodes.
If anything else occurs I will post it here.
If anything else occurs I will post it here.
10-08-21, 09:47 AM
#50
Lexus Test Driver
Parasitic draws can be a lot of work to track down and intermittent draws are the worst kind.
Like Salim and others say above, isolating the draw to a circuit is key by pulling fuses one by one. The hard part is many of the car's systems stitch together thru the Body ECU once the fuses are located at the draw. In the RX330 forum there have been Body ECU failures and also door module failures that can "wake up" the Body ECU circuit intermittently.
* There is a door modue located in all 4 doors.
Like Salim and others say above, isolating the draw to a circuit is key by pulling fuses one by one. The hard part is many of the car's systems stitch together thru the Body ECU once the fuses are located at the draw. In the RX330 forum there have been Body ECU failures and also door module failures that can "wake up" the Body ECU circuit intermittently.
* There is a door modue located in all 4 doors.
10-08-21, 10:48 PM
#51
Driver
Thread Starter
I haven't bothered to leave the fuses out because the fuses at fault are a large part of the draw. Pull one and its down 30%, pull the other and its down 30% (rufly). I did shut and lock the doors yesterday after plugging things back in,(radio, display, heater,cd-player etc.) came back 1/2 hour later and it was at 38 to 40 ma. I could be wrong but I really think putting in the new diode pack in the alternator helped because even though the alt tested good, I set the body of the alt on the pos post of the battery and got voltage through the cable terminal, then reversed it, terminal on battery test lead to body of alt and got voltage. One thing I havent said here is that it is a replacement alt was a denso and had a 6 diode pack, this new pack has 8 diodes.
If anything else occurs I will post it here.
If anything else occurs I will post it here.
Did you measure current flow backwards from the battery to the alternator (with the engine off and the car secured)?
A bad diode would likely conduct some current backwards, causing a drain I imagine?
You mentioned CAR LOCKED. I am still trying to figure out of the car is SUPPOSED to run the battery down if the doors are CLOSED but NOT LOCKED?
Does the act of locking disconnect certain circuits or modules?
Bob
10-08-21, 11:06 PM
#52
Driver
Thread Starter
Parasitic draws can be a lot of work to track down and intermittent draws are the worst kind.
Like Salim and others say above, isolating the draw to a circuit is key by pulling fuses one by one. The hard part is many of the car's systems stitch together thru the Body ECU once the fuses are located at the draw. In the RX330 forum there have been Body ECU failures and also door module failures that can "wake up" the Body ECU circuit intermittently.
* There is a door module located in all 4 doors.
Like Salim and others say above, isolating the draw to a circuit is key by pulling fuses one by one. The hard part is many of the car's systems stitch together thru the Body ECU once the fuses are located at the draw. In the RX330 forum there have been Body ECU failures and also door module failures that can "wake up" the Body ECU circuit intermittently.
* There is a door module located in all 4 doors.
I chased an intermittent draw that would be fine for weeks, then drain my battery overnight.
Turned out the seat control modules can go bad and do that, and are "hot" all of the time so the seats can be adjusted before the engine is started. Many people on the Forum spent $2000 to replace the front seat modules ($600+ per module plus labor) to cure the problem, in fact. Then China produced knock-offs for about $100 that were perfect copies and worked as well. I don't know if they make any replacement modules for our cars, however.
As our cars age, all those electronics become an achilles heel I fear.
Too bad there is not a way to isolate ONLY the bare minimum circuits needed to be active and connected to the battery with the key OFF, and have the rest activated with a relay ONLY when the ignition is turned on in anticipation of using the vehicle. It would be analogous to the "Master Switch" in an aircraft (I apologize for the non-PC term, but that is what it is still called) where the battery is essentially isolated via a large continuous duty solenoid. These are available with up to 200a ratings and only draw about one amp in operation (zero of course when "Off"). All of the non-essential circuits could be powered through it, and it could be switched by the ignition switch? Just thinking that if it could eliminate a fortune on an ecu module, or a body module it would be worth it? It may be entirely impractical given the complexity of the wiring, of course.
10-09-21, 08:09 AM
#53
Lexus Test Driver
Short Pin Fuse for discussion and compare
I know in Mercedes that is TRUE.
I chased an intermittent draw that would be fine for weeks, then drain my battery overnight.
Turned out the seat control modules can go bad and do that, and are "hot" all of the time so the seats can be adjusted before the engine is started. Many people on the Forum spent $2000 to replace the front seat modules ($600+ per module plus labor) to cure the problem, in fact. Then China produced knock-offs for about $100 that were perfect copies and worked as well. I don't know if they make any replacement modules for our cars, however.
As our cars age, all those electronics become an achilles heel I fear.
Too bad there is not a way to isolate ONLY the bare minimum circuits needed to be active and connected to the battery with the key OFF, and have the rest activated with a relay ONLY when the ignition is turned on in anticipation of using the vehicle. It would be analogous to the "Master Switch" in an aircraft (I apologize for the non-PC term, but that is what it is still called) where the battery is essentially isolated via a large continuous duty solenoid. These are available with up to 200a ratings and only draw about one amp in operation (zero of course when "Off"). All of the non-essential circuits could be powered through it, and it could be switched by the ignition switch? Just thinking that if it could eliminate a fortune on an ecu module, or a body module it would be worth it? It may be entirely impractical given the complexity of the wiring, of course.
I chased an intermittent draw that would be fine for weeks, then drain my battery overnight.
Turned out the seat control modules can go bad and do that, and are "hot" all of the time so the seats can be adjusted before the engine is started. Many people on the Forum spent $2000 to replace the front seat modules ($600+ per module plus labor) to cure the problem, in fact. Then China produced knock-offs for about $100 that were perfect copies and worked as well. I don't know if they make any replacement modules for our cars, however.
As our cars age, all those electronics become an achilles heel I fear.
Too bad there is not a way to isolate ONLY the bare minimum circuits needed to be active and connected to the battery with the key OFF, and have the rest activated with a relay ONLY when the ignition is turned on in anticipation of using the vehicle. It would be analogous to the "Master Switch" in an aircraft (I apologize for the non-PC term, but that is what it is still called) where the battery is essentially isolated via a large continuous duty solenoid. These are available with up to 200a ratings and only draw about one amp in operation (zero of course when "Off"). All of the non-essential circuits could be powered through it, and it could be switched by the ignition switch? Just thinking that if it could eliminate a fortune on an ecu module, or a body module it would be worth it? It may be entirely impractical given the complexity of the wiring, of course.
From what I hear it's not really a fuse but more of a jumper but I have not confirmed this either way but it will knock out the body ecu(1 of the power wires), radio & amp, and dome light circuits. So if anything tries to "wake up" the body ecu from these circuits or if the body ecu is waking up on it's own(faulty) this kills it dead- maybe helpful to at least narrow it down. Add- The ECU-B fuse also goes to all 4 doors and effects the Body ECU when the key is off position. I think.
Also, pulling short pin is very handy to decrease power draw doing stuff that requires the key to be left on for a long time.
As far as the door ecu/modules they are fused a different path from short pin so pulling the short pin won't help with those but they can't wake up the body ecu with the short pin pulled.. Edit- Add- the ECU-B fuse does however go to all 4 door modules.
I've heard members report bad amps doing a parasitic draw too. Intermittent ones seem to be door modules many times or the Body ECU itself(cheap used on ebay) and a variety of other things.
Just rambling some ideas.
Last edited by Margate330; 10-09-21 at 06:31 PM.
10-09-21, 06:02 PM
#54
Driver
Thread Starter
This closest I've seen thing to a "cut off" is the Short Pin Fuse located in the fuse box under the hood(see attached).
From what I hear it's not really a fuse but more of a jumper but I have not confirmed this either way but it will knock out the body ecu, radio & amp, and dome light circuits. So if anything tries to "wake up" the body ecu from these circuits or if the body ecu is waking up on it's own(faulty) this kills it dead- maybe helpful to at least narrow it down.
Also, pulling short pin is very handy to decrease power draw doing stuff that requires the key to be left on for a long time.
As far as the door ecu/modules they are fused a different path from short pin so pulling the short pin won't help with those but they can't wake up the body ecu with the short pin pulled..
I've heard members report bad amps doing a parasitic draw too. Intermittent ones seem to be door modules many times or the Body ECU itself(cheap used on ebay) and a variety of other things.
Just rambling some ideas.
From what I hear it's not really a fuse but more of a jumper but I have not confirmed this either way but it will knock out the body ecu, radio & amp, and dome light circuits. So if anything tries to "wake up" the body ecu from these circuits or if the body ecu is waking up on it's own(faulty) this kills it dead- maybe helpful to at least narrow it down.
Also, pulling short pin is very handy to decrease power draw doing stuff that requires the key to be left on for a long time.
As far as the door ecu/modules they are fused a different path from short pin so pulling the short pin won't help with those but they can't wake up the body ecu with the short pin pulled..
I've heard members report bad amps doing a parasitic draw too. Intermittent ones seem to be door modules many times or the Body ECU itself(cheap used on ebay) and a variety of other things.
Just rambling some ideas.
I have the full factory manual for a 2001 RX300 and did not see a page like that (but with 3 large volumes plus the collision repair book, it's easy to miss). My car is a 2003, and I know that there ARE changes between 2001 and 2003, but the book fell into my hands FREE, so I couldn't pass it up!
That "Short Pin" could maybe be replaced by a small DIN relay (about 1" square and 2" high) with 12v on pins 85 and 86 activating the relay, and 30 to 87 being the power-carrying pins. These will handle 30 amps and are continuous duty.
Since you didn't mention that the short pin doesn't knock out the engine ecu, I wonder if the car would start and run with it pulled (or open via a switched relay)? I would love a way to be able to disable all the probably parasitic drain circuits (say if I leave the car for weeks at an vallet airport lot where you cannot park or retrieve your own car so it can be started and driven, but the battery won't go dead).
10-09-21, 06:38 PM
#55
Lexus Test Driver
I haven't yet looked under my hood (the diagram says the Short Pin is in the "Engine Room Junction Box"), but is it labeled as such, or how do I identify it?
I have the full factory manual for a 2001 RX300 and did not see a page like that (but with 3 large volumes plus the collision repair book, it's easy to miss). My car is a 2003, and I know that there ARE changes between 2001 and 2003, but the book fell into my hands FREE, so I couldn't pass it up!
That "Short Pin" could maybe be replaced by a small DIN relay (about 1" square and 2" high) with 12v on pins 85 and 86 activating the relay, and 30 to 87 being the power-carrying pins. These will handle 30 amps and are continuous duty.
Since you didn't mention that the short pin doesn't knock out the engine ecu, I wonder if the car would start and run with it pulled (or open via a switched relay)? I would love a way to be able to disable all the probably parasitic drain circuits (say if I leave the car for weeks at an vallet airport lot where you cannot park or retrieve your own car so it can be started and driven, but the battery won't go dead).
I have the full factory manual for a 2001 RX300 and did not see a page like that (but with 3 large volumes plus the collision repair book, it's easy to miss). My car is a 2003, and I know that there ARE changes between 2001 and 2003, but the book fell into my hands FREE, so I couldn't pass it up!
That "Short Pin" could maybe be replaced by a small DIN relay (about 1" square and 2" high) with 12v on pins 85 and 86 activating the relay, and 30 to 87 being the power-carrying pins. These will handle 30 amps and are continuous duty.
Since you didn't mention that the short pin doesn't knock out the engine ecu, I wonder if the car would start and run with it pulled (or open via a switched relay)? I would love a way to be able to disable all the probably parasitic drain circuits (say if I leave the car for weeks at an vallet airport lot where you cannot park or retrieve your own car so it can be started and driven, but the battery won't go dead).
The Body ECU has 3 power wires from different fuses that appear to power the Body ECU differently depending on what mode it is in- Key on ACC, Key on IGNITION, or off.
Turns out the ECU-B fuse does also go to all 4 doors too, found that on a different page. I believe the ECU-B is the Body ECU power wire for when the key is off.
If I was leaving it somewhere I would unhook the battery altogether.
-> Here is the year 2002 RX300 detail for the Short Pin and showing some power distribution. On the RX330 it is in the fuse box under the hood and labeled, hope yours is too.
10-09-21, 07:49 PM
#56
Driver
Thread Starter
I am OK with disconnecting the battery for my own use (and frankly HAVE done that in he past), but I would like to be able to leave the car at places like airports where the car has to be left with a valet for parking and returned upon arrival, making batter disconnection impractical. I used to use one of those devices that hooks to the battery, and the battery cable attaches to the other end, and a **** is loosened to break the connection. ( See: https://tinyurl.com/yn7jvz5j )
If I could find a way to disable the most likely suspects perhaps via a relay (and verify it by trying it long enough to be reasonably sure it was indeed the problem) while maybe permitting it to be run for short periods, it would be reassuring.
So in YOUR 2002 it is labeled "Short Pin?"
I will check in the morning and see what removing/unhooking it (not sure physically what it looks like at this point) kills and if the car will start and run.
If I could find a way to disable the most likely suspects perhaps via a relay (and verify it by trying it long enough to be reasonably sure it was indeed the problem) while maybe permitting it to be run for short periods, it would be reassuring.
So in YOUR 2002 it is labeled "Short Pin?"
I will check in the morning and see what removing/unhooking it (not sure physically what it looks like at this point) kills and if the car will start and run.
10-09-21, 08:00 PM
#57
Lexus Test Driver
I am OK with disconnecting the battery for my own use (and frankly HAVE done that in he past), but I would like to be able to leave the car at places like airports where the car has to be left with a valet for parking and returned upon arrival, making batter disconnection impractical. I used to use one of those devices that hooks to the battery, and the battery cable attaches to the other end, and a **** is loosened to break the connection. ( See: https://tinyurl.com/yn7jvz5j )
If I could find a way to disable the most likely suspects perhaps via a relay (and verify it by trying it long enough to be reasonably sure it was indeed the problem) while maybe permitting it to be run for short periods, it would be reassuring.
So in YOUR 2002 it is labeled "Short Pin?"
I will check in the morning and see what removing/unhooking it (not sure physically what it looks like at this point) kills and if the car will start and run.
If I could find a way to disable the most likely suspects perhaps via a relay (and verify it by trying it long enough to be reasonably sure it was indeed the problem) while maybe permitting it to be run for short periods, it would be reassuring.
So in YOUR 2002 it is labeled "Short Pin?"
I will check in the morning and see what removing/unhooking it (not sure physically what it looks like at this point) kills and if the car will start and run.
On my car(RX330) it looks like all the other fuses except it says Short Pin on the fuse box cover and is located in the engine compartment on driver side.
If I remember correctly the car will still run and only unhooks everything downstream from the Short Pin as shown.
Let me know if you need a pic of the actual Short Pin and plz let us know what you find.
10-09-21, 10:37 PM
#58
Driver
Thread Starter
The drawing above is for 2002 RX300 found in the Power Source section.
On my car(RX330) it looks like all the other fuses except it says Short Pin on the fuse box cover and is located in the engine compartment on driver side.
If I remember correctly the car will still run and only unhooks everything downstream from the Short Pin as shown.
Let me know if you need a pic of the actual Short Pin and plz let us know what you find.
On my car(RX330) it looks like all the other fuses except it says Short Pin on the fuse box cover and is located in the engine compartment on driver side.
If I remember correctly the car will still run and only unhooks everything downstream from the Short Pin as shown.
Let me know if you need a pic of the actual Short Pin and plz let us know what you find.
I found the location in that fusebox (below) so I'll check it out tomorrow.
Thanks for opening this Short Pin discussion.
https://bobinyelm-yahoo.tinytake.com...504&height=709
https://bobinyelm-yahoo.tinytake.com...494&height=543
10-11-21, 05:32 AM
#59
Driver School Candidate
Diode pack
Did you JUST replace the diodes? Where did you get the diode pack?
Did you measure current flow backwards from the battery to the alternator (with the engine off and the car secured)?
A bad diode would likely conduct some current backwards, causing a drain I imagine?
You mentioned CAR LOCKED. I am still trying to figure out of the car is SUPPOSED to run the battery down if the doors are CLOSED but NOT LOCKED?
Does the act of locking disconnect certain circuits or modules?
Bob
Did you measure current flow backwards from the battery to the alternator (with the engine off and the car secured)?
A bad diode would likely conduct some current backwards, causing a drain I imagine?
You mentioned CAR LOCKED. I am still trying to figure out of the car is SUPPOSED to run the battery down if the doors are CLOSED but NOT LOCKED?
Does the act of locking disconnect certain circuits or modules?
Bob
10-11-21, 08:37 AM
#60
Moderator
Diode pack
Lexus/Toyota sells OEM diode pack and set of brushes too. I would change the brushes if you have reached 100k+ miles [just because you are servicing].
Salim
Salim