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Discussion Starter #1
I have posted in other threads and asked the question in various forms with no responses yet. This is partially because I am still investigating and narrowing down possibilities so bear with me.

For about the last month or so i have been noticing that my battery has been drained after sitting for 1 or 2 days. It has always started but has been slow to crank. I would turn off all accessories (heater and radio), wait a minute and try again and it would fire up, still slow cranking but enough to start. The old battery was about 3 years old (autozone, duralast gold) so i bought a new one. I noticed that the acid was low after i removed it, but decided to replace it anyways, so much for "maintenance free".

I started noticing this after having issues with the factory alarm. During a rainy day, the alarm would go off at random. On other occasions, the horn would not beep when i locked the car. I have since determined that my hood latch sensor is dead. I removed the latch, cleaned it up and reinstalled it but the sensor was still crap. I disconnected the harness for now to keep the neighbors happy.

The only aftermarket item on my car is an "XM Commander" which is wired in through the fuse box with jumper wires to power and accessory, no problems with this device indicating a short or fault.

Since replacing my battery and disconnecting the hood latch sensor, i have not had any alarm issues. I have noticed that it is still slow cranking (just not as bad as before) after sitting for 1 or 2 days.

Should i use a jumper wire at the hood latch? This should not matter, but maybe it does. When i checked the trunk sensor, the circuit is closed when the trunk is closed, allowing 12v to flow through it. When you disconnect the hood sensor, it does not affect the alarm system, but also doesn't allow the 12v signal through.

Does anyone have any other suggestions for testing or diagnosing this issue. I'm sure the new battery will help cold starts but i have to wonder for how long. Thanks for reading, any input would be helpful.
 

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Discussion Starter #3
It is possible that my only problems were a dying battery and faulty hood latch and i am now paranoid and over thinking this... but any advice or suggestions are still welcome.
 

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Discussion Starter #4
The car is at the dealer this weekend for diagnosis. I will post an update soon for anyone interested.
 

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Discussion Starter #5
My problem may have been RESOLVED! I have only 2 aftermarket components in the car, a USA SPEC Ipod Interface connected to the factory radio, and an XM Commander satellite radio which connects audio through the Ipod Interface rca jacks and has independent power and accessory hooked up through the fuse panel.

The service advisor told me that something was keeping the radio awake after the car shuts down which leads me to believe it would be the Ipod Interface connected to the radio. I explained how everything was connected so hopefully by tomorrow they can narrow down which component it is (XM or Ipod). She said it was the XM unit keeping the radio on, but i think that's because they did not understand that it was not connected directly to the radio, only the Ipod Interface is. It is still possible that the XM unit is constantly drawing power from the fuse panel, but that's not what she made it sound like. I don't think it's possible for the XM Unit to affect the radio through the Ipod interface.

Confirmation will follow when I get my car back! Hopefully this helps someone down the road.
 

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I started noticing this after having issues with the factory alarm. During a rainy day, the alarm would go off at random. On other occasions, the horn would not beep when i locked the car. I have since determined that my hood latch sensor is dead. I removed the latch, cleaned it up and reinstalled it but the sensor was still crap. I disconnected the harness for now to keep the neighbors happy.
not trying to change the subject but i dont think our TSX horn beeps when pressing the lock button... at least mines dont but maybe its an 04-05 thing?
 

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Discussion Starter #7
04 TSX horns beep, i hear the newer models use a separate beeper. If the horn does not honk when pressing the lock button twice, then there is a fault in the security system somewhere. I'm not sure if this applies to the newer models though, but definitely the 04.
 

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Truth...I wish we had the beep though! Much more conspicuous, haha.
 

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If anything else happens, first thing you should do is take out the AMP fuse!
It will stop your battery drainage!
 

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Discussion Starter #10
Bad news, apparently the dealer was unable to duplicate my problem. My car sat there all weekend and never showed an amp draw. Go figure, It's been dying slowly every day in my driveway, but it's fine at the dealership, what are the odds! They told me to install a new hood latch just to rule out the dead switch.

I wish i had gotten a better answer, but they pretty much told me that "something" was triggering the B-CAN system to wake up or stay awake sometimes. They suspect that my faulty hood latch switch may be responsible. However they have no evidence to support this theory.

To the best of my knowledge, the security system will only detect a change in one of the sensors (opening or closing a door, hood, trunk after the system has been armed). The switches in the door, hood and trunk are all simple open or closed type switches. The system sends 12v through each switch and it either passes through an open switch or is stopped by a closed switch. either way, the system will arm as normal. the only thing that sets the alarm off is a change in the circuit, one way or another.
 

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Discussion Starter #11
excerpt from ServiceNews article

Excessive Parasitic Draw? Check If the B-CAN System Is
Awake
Currently Applies To: ’06–09 MDX, ’07–09 RDX, ’05–09 RL, ’04–08 TL, and ’04–09 TSX
When it comes to parasitic draw, the body controller area network (B-CAN) system—first introduced in the ’04
TSX—is a major contributor. With the ignition switch turned to LOCK (0), all B-CAN-related components still
receive battery power. This gives the various control units such as the gauge control module, the multiplex
integrated control unit (MICU), the door multiplex control unit, the climate control unit, the power seat control unit,
etc., a means of communicating when, for instance, a power door lock switch input signal changes or there’s a
signal received from a keyless remote transmitter. Knowing what the B-CAN system does when you turn the
ignition switch to LOCK (0) will help you to recognize if it’s causing an excessive parasitic draw problem. Normal
parasitic draw on a battery varies from model to model, depending on the number of control units involved. Just
remember if the draw is less than 50 mA, it’s normal; if it’s 50 mA or more, it’s excessive.
Wake-up Mode and Sleep Mode
The B-CAN system has two operating modes to reduce parasitic draw: the wake-up mode and the sleep mode.
With the ignition switch turned to ON (II), the system is in the wake-up mode. During this time, the system has both
+B power (HOT AT ALL TIMES) and IG1 power (HOT WITH IGNITION SWITCH ON) and there’s a parasitic draw
on the battery of about 200 mA or more. When you turn the ignition switch to LOCK (0), the system stays awake as
long as the key-off timer (part of the MICU) is running. The key-off timer shuts off when the B-CAN system receives
a door switch open input signal; otherwise, it shuts off right at 10 minutes. With the system now in the sleep mode,
the parasitic draw on the battery drops to less than 50 mA. It still has +B power (HOT AT ALL TIMES), though,
and there are a number of signal inputs that can wake it up to do some work. A good example is the power door
lock switch. When you push the switch to its lock or unlock position, the system wakes up, does whatever it needs
to do, and then goes back to sleep 5 seconds later.
Don’t Just Rely on Component Replacement
Many service techs replace B-CAN-related components because they think those components are causing the
excessive parasitic draw. When checking for excessive draw, they find that by pulling the backup fuse to the MICU,
the parasitic draw drops to normal. What they don’t realize, though, is that the real cause for the B-CAN system
staying awake could be a stuck door lock switch. If that door lock switch sticks in either its lock or unlock position
(the input signal stays on), the system won’t return to the sleep mode. This will keep an excessive parasitic draw on
the battery that will kill it in short order. Just how long that actually takes depends on the battery’s state of charge
and other variables. A parasitic draw of about 200 mA will usually kill a battery in about 2 days. So the bottom line
is this: When it comes to excessive parasitic draw, you can’t rely on component replacement to always fix things.
Even though the suspected component was replaced, there’s still an excessive parasitic draw problem that will
probably wind up in a comeback . . . not to mention one very unhappy service client.
Narrowing Things Down
An easy way to find out if the B-CAN system is staying awake—and causing an excessive parasitic draw
problem—is to momentarily short one B-CAN communication wire to ground. There are two types of
B-CAN systems: a slower (33.33 kbps) single-wire system, and a faster (125 kbps) two-wire system, which was
first introduced in the ’09 TSX. Shorting the single wire to ground (single-wire system) or the CAN_H wire to ground
(two-wire system) at any of the B-CAN-related components stops all B-CAN communication and puts all of the
control units into the sleep mode. If doing this gets rid of the excessive parasitic draw, then an input signal to one of
the control units or a control unit itself is keeping the system awake.
Finding the Culprit
There are two ways to find out which control unit is keeping the B-CAN system awake. One way is to use the All
Data List in the HDS to check for any abnormal switch inputs such as a door lock switch that stays on. Such inputs
will keep the system awake. The other way is to start unplugging the components on the B-CAN circuit one at a
time. When you unplug the suspected control unit, the rest of the B-CAN-related components will fall sleep. Make
sure there are no abnormal switch inputs to that control unit, though, such as a door lock switch that stays on,
otherwise the B-CAN system will stay awake.

Some Handy Tips
Without a doubt, chasing down an excessive parasitic draw problem can be time-consuming, even frustrating work.
Here are some handy tips to help make that job go just a little easier:
• Use the Auto Battery/Electrical System Analyzer (ED-18) to make sure the vehicle’s battery and charging
system are OK.
• Check to see if the vehicle has any aftermarket accessories. If it does, let the service consultant know right
away. He or she will need to get permission from your client before you can unplug or remove those
accessories.
• If the vehicle has a security system, make sure you unplug the hood switch to simulate a closed hood.
• To check for excessive parasitic draw, use the LH41A AC/DC Low Current Clamp Meter (Model No.
FLULH41A), a required special tool. Only clamp meters that match the LH41A’s resolution and accuracy specs
can be used to measure parasitic draw. See Meet the LH41A Clamp Meter! below for details.
• Check the vehicle under the same conditions reported by your client or written on the RO (for example, your
client reported all the doors were locked and the security system was turned on).
• After turning the ignition switch to LOCK (0), open and close the driver’s door to shut off the key-off timer.
On most vehicles, this will cut the time it takes for the B-CAN system to go into the sleep mode.
 

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what are your driving habits? I ask because I was having the same issue with my wife's 04 TSX a few years back. At that time she used to drive about 4 miles daily back and forth to the communter train station. Whenever we would go away for a weekend, or if her car sat for the the weekend while we used my car her battery would require a jump. Brought it to the dealer several times and they told me it was my aftermarket alarm/remote start. I took that out and it still did it. When she switched jobs and started driving 15 miles each way to work it stopped happening. So I don't think the problem is resolved, but apparently now she drives long enough for the alternator to sufficiently charge the battery.
 

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Discussion Starter #13
Well I can drive the car 50 miles somewhere, let it sit over night and it will start, but it cranks very slow. Dealer was unable to duplicate my problem though. They could not find any excessive amp draw while they had it. I now think my problem may be the starter, being that i have 120k miles on the car. Once the car has been driven for 15 minutes or so and the engine is nice and warm, it will usually restart fine. It's only on cold starts that i have the problem and it sounds just like a dying battery. So i still have no answers and i have replaced the hood latch switch with the same outcome as before.
 

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my 2008 TSX was at the dealer today, parasitic draw was on the list of things to do.

long story short, dealer said because I have Tein EDFC, it could be my fault, and it's
$105 an hour to diagnose the issue, which could take up to 12 hours, lol.

I have an ipod, I think the usa spec? setup, tein edfc, blah, blah, but whatever, the
car has always died, since I first had it.

no idea what it could be.

I'm drawing about 145 milliamps when the car is "fully asleep."

20-30 is normal, up to 50 is acceptable by Acura.
 

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PhisaggiN
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my 2008 TSX was at the dealer today, parasitic draw was on the list of things to do.

long story short, dealer said because I have Tein EDFC, it could be my fault, and it's
$105 an hour to diagnose the issue, which could take up to 12 hours, lol.

I have an ipod, I think the usa spec? setup, tein edfc, blah, blah, but whatever, the
car has always died, since I first had it.

no idea what it could be.

I'm drawing about 145 milliamps when the car is "fully asleep."

20-30 is normal, up to 50 is acceptable by Acura.
Isn't the USAspec supposed to shut down after an hour of charging with the car off? Ive always wondered if that or the iSimple still draws power after an hour.


:fro:
 

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Discussion Starter #16
Well since starting this thread, I actually found that my car did not have any abnormal parasitic draw, my problem was actually the Starter going bad. I did however learn alot about diagnosing parasitic draw! Go buy yourself a good Multimeter somewhere. I bought a clamp on Amp Meter from Sears and it was junk, not nearly sensitive enough to diagnose mA draw for a car. Just buy a regular old Meter with the ability to detect Amp Draw... usually they have a 10A and 150mA range. Get some clips to connect your meter to the battery cable and then the post and start pulling fuses after letting the car sit for 10-20 minutes to let it go to "sleep".
 

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I'm having a parasitic draw problem that appears to be coming from the radio. My mechanic took the radio fuse out to stop the draw but now I have no radio. I had an aftermarket audiovox 1500 installed to my radio so that I could get bluetooth music for my phone. Is it possible that this aftermarket part is staying awake and causing the draw? Also I noticed the fuse is 20A for the radio. Is it also possible that 20A is not enough once the aftermarket part is installed which is causing the problem?
 

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*UPDATE*

I went to the shop that installed the audiovox and explained the situation to them. They disconnected the audiovox for me. I then took my car back to the mechanic. He plugged the radio back in so that it gets power now.

This should isolate whether or not the factory radio is going to sleep after car is shut off. If there is any parasitic draw from the factory radio then the car battery won't start tomorrow. I hope it's the audiovox mediabridge that is causing the parasitic draw. If not, then it seems like the only solution is to replace the whole radio/navi. :( I hope not as those are expensive.

If it's the mediabridge then I'm wondering whether or not I should get that replaced or just throw it out and find another solution for bluetooth audio. The reason why I think it was installed incorrectly is because when it was first installed the audio sounded like it was underwater and dirty when playing through bluetooth.

Can the radio just go bad like that and all of a sudden not go to sleep?
 

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thanks for great info, my 06 TSX had parasitic 200mA draw from #5 light /radio fuse , disconnected hands free in passenger kick panel and went to 16mA when in sleep mode
 

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Just an FYI to those with driver window switch issues that may be causing this. Went to local pull-it and got the assembly from an 05 Accord and it worked perfectly. Part numbers differ slightly. Battery drain seems to be solved after 5 days. Cheap fix $20.00.
 
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