High idle current draw on Gen5 camry

[yotomac]

Hi,
I have a 2005 Camry XLE v6 that has been draining down the battery lately. I checked the idle current draw and found its about 320mA. Does anyone know what the general range should be?

I took the reading with all doors closed (no lights), engine off and nothing switched on except the systems that require constant power. The car has an aftermarket radio (Pioneer AVIC D1) installed (which has a line tied to the constant power source). At this setting, I suppose only the clock and the security system should be ON, but shouldn't those systems draw very little power? ... I looked through the Hayne's manual but couldn't find anything about idle current draw.

Thanks in advance for you help.

[andym1978]

That's around 5 watts, which isn't very high (about the power of a flash light). If I remember correctly, the car computer is always drawing power to handle things like door lock signals (from the remote) and such. How old is your battery? Has it ever been accidentally drained? Some batteries will permanently lose more than half of their life just from one drain due to leaving lights on, etc.

[Mike Gerber]

What you are referring to is called the "Dark Current Draw". It's the amount of current the car uses with the engine off. It's to keep things in memory like the main computer and things like the radio presets in the radio's memory. The general rule of thumb I have heard on most cars is 25mA or less. 320mA is too high. I would suspect wiring to your aftermarket radio or an aftermarket alarm system, if the car has one. I would pull the fuse for the aftermarket radio and recheck the Dark Current Draw. I would do the same if you have an aftermarket alarm system.

Mike

[andym1978]

@Mike

Interesting info. Very good to know if I need to troubleshoot a similar problem in the future.

[yotomac]

@Mike
Thanks a lot for pointing out the term (I can now search for similar cases).


I spent the last two hours pulling out every fuse and checking the dark current draw:

* With all fuses in place and doors closed (engine off, no key in ignition), the dark current draw starts off at around 280mA ... then drops off to 170mA in about 10-15 seconds (and holds at that current indefinitely).
- The symptom to me looks like some kind of capacitor charging initially and then reaches a steady state.

* None of the other circuits seems to affect this behavior. I finally pulled the ECU-B fuse (10A fuse), and the dark current draw dropped to 4mA.

I know there are lot of systems connected to the ECU such as the factory installed security system and the remote keyless entry, but I couldn't find any fuses relating to these systems. Would it be possible that the ECU is bad?

Thanks!

[Mike Gerber]

"Would it be possible that the ECU is bad?"

I'm not really sure. Are there any other problems with the car? How does it run? Is the check engine light on? Is there anything wired in to the ECU's wiring? Did you check the aftermarket radio; sometimes they have an old fashioned inline fuse? I really wouldn't want you to go buy another ECU just for a test; they are not cheap.

Perhaps someone else on this forum with another generation 5 V6 Camry XLE can do a dark current test for you as a comparison.

Mike

[yotomac]

The car runs perfectly fine and the check engine light is off (never had a check engine light situation). I don't see anything wired to the ECU either.

I inspected the after-market radio install multiple times and I in fact taped everything carefully (I even taped the wiring harness just to be sure). When I did the diagnostics, I disconnected the radio fuse (there are actually two radio fuses, and I disconnected both of them), so the radio should be completely out of the picture.

Like I said, when I pull the ECU-B fuse, the dark current goes to almost nothing. Here's what the owner's manual says about the ECU-B fuse:

"23. ECU−B 10 A: Multiplex communication
system (power door lock system, security system, auto−door locking system, automatic light control system, head- light delay off system, tail light auto cut system, illuminated entry system, daytime running light system, wireless remote control system), air conditioning system"

From what I can glean off of multiple sources, 170mA is still too high a current... the expected value should be around 40mA. However, I am not absolutely sure. Like you said, perhaps someone in this forum can figure out what the usual range should be... that will be the best outcome for me.

Thanks

[jdhopki]

Have you checked the amp fuse. I had a problem with my 2007 XLE when the torsion spring in the trunk came lose and shorted out the left rear speaker. My left rear speaker blew and remained hot with the key out. I removed the amp fuse and the heat problem went away. I suspect that the amp is causing the problem and needs to be replaced.
I think there is a trouble report out on the current draw problem

[loubapache]

I do not know the Camry system much but have studied the CAN BUS system and troubleshooted many similar problems for German makers. I believe most auto makers use similar design concept.

In general, the acceptable ghost draw should be around 35 mA - 55 mA, plus or minus a few, depending on makers and models. Most of the time, excessive draws are caused by some convenience features (modules) because they remain powered when the car is off and into sleep mode. These convenience modules should go to sleep as well after some pre-determined time interval. When one of these modules mal-functions and does not go to sleep mode, then it draws excessive current and drains the battery.

In your case, you have identified the fused circuit that is causing the current draw. However, the problem could be caused by (based on your fuse description) the power door lock system, the security system, the auto−door locking system, the automatic light control system, the head- light delay off system, the tail light auto cut system, the illuminated entry system, the daytime running light system, the wireless remote control system. Each of these systems could have a separate module or several of thee system could share a module.

In the maker and models I am very familiar with (I used to be a forum moderator for the make/models), the power seat, power window, and the wireless remote sensors are the frequent causes of such problems.

Typically, the best way is to use a factory scanner to diagnose the problem because the module might leave a trouble code that only the factory (or some similar one but not OBDII) scanner can retrieve. This may not be possible for an average DIYer.

Then the next possible way to troubleshoot is to identify all the above modules and unplug one at a time from that fused circuit (but leave the fuse back in) and then measure the ghost draw to see if it reduces the current. When you unplug a module and the drain decreases substantially, you have found a circuit with excessive parasitic current.

Remember that the car must be in sleep mode so anytime you open a door a something like that, it wakes up the car. Sometimes, it could takes minutes to even hours for some cars to go complete sleep.

Hope this helps.

[Mike Gerber]

"Then the next possible way to troubleshoot is to identify all the above modules and unplug one at a time from that fused circuit (but leave the fuse back in) and then measure the ghost draw to see if it reduces the current."

I was thinking of that type of test as I was reading your post.

Mike

[yotomac]

Originally Posted by loubapache

In general, the acceptable ghost draw should be around 35 mA - 55 mA, plus or minus a few, depending on makers and models. Most of the time, excessive draws are caused by some convenience features (modules) because they remain powered when the car is off and into sleep mode. These convenience modules should go to sleep as well after some pre-determined time interval. When one of these modules mal-functions and does not go to sleep mode, then it draws excessive current and drains the battery.

In your case, you have identified the fused circuit that is causing the current draw. However, the problem could be caused by (based on your fuse description) the power door lock system, the security system, the auto−door locking system, the automatic light control system, the head- light delay off system, the tail light auto cut system, the illuminated entry system, the daytime running light system, the wireless remote control system. Each of these systems could have a separate module or several of thee system could share a module.

In the maker and models I am very familiar with (I used to be a forum moderator for the make/models), the power seat, power window, and the wireless remote sensors are the frequent causes of such problems.

That actually explains a lot of the symptoms. I believe the problem is somewhere in one of: A/C module, wireless remote system, or security system. From what I can tell, the power door and power seats have a separate circuit and a separate fuse. When I disconnect the fuse to those circuits, the current draw remains the same. The Haynes manual doesn't go much into the wiring diagrams, so I cannot find the exact circuits to disconnect and test.

Oh well, I scheduled a service appointment with the local Toyota dealer. Lets see how that goes. Thanks everyone for your help. I will post what the tech has to say once I get it checked.

I wanted to empower myself with some knowledge before I seek the last resort (of going to a mechanic).

[honyota]

I'm experiencing the same problem as yotomac with my 2008 Sienna, with the exception that everything is factory stock. Yoto, please let us know if your problem was resolved and how it was fixed. Does anyone else out there have any additional ideas how to further troubleshoot this without having to scan$$?
Additionally, I was wondering how long it takes the Sienna to go to sleep?
Thanks in advance!