What's new

2008 Acura MDX Parasitic Draw

KDXSR5

Vertical Scope Hater
Joined
May 21, 2020
Member Number
1004
Messages
117
Loc
WYOMING
We have a 2008 Acura MDX that sits a lot. The battery will go dead if it is not driven often (daily). Even with a solar charger on it, the battery will die.

I did a parasitic draw test on it today, and found what I believe is the culprit circuit. The #4 fuse in the underhood fuse box closest to the battery is drawing 2.6A even with the ignition off and the key out. If I pull this fuse, total amp draw drops to 0.002A (2 Miliamps), which seems pretty reasonable.

I know this is a long shot, but I am wondering if anyone else has a 2008ish MDX and could check to see what total amp draw is with the #4 fuse installed and not installed.

Time to find some wiring diagrams and start tracing the circuit out. :shakeshead:
 
It goes to radio, door locks, and interior lights. Until I get this figured out, I am just going to pull the fuse. Don't need any of those features unless we are using this vehicle for a trip or something (rare).
 
It goes to radio, door locks, and interior lights. Until I get this figured out, I am just going to pull the fuse. Don't need any of those features unless we are using this vehicle for a trip or something (rare).
its not just that.

Fuse 4 is a 40a fuse right?

according the diagrams i have.

Fuse #4 of the underhood fuse panel is a 40a fuse and it feeds power to a bunch of shit. The wire coming from the the upper right of the sceen is coming out of fuse 4 after it also feeds fuse 8 for the VBU
acura mdx.JPG


Dont pay attention to the highlighted shit i didnt mean to do that
 
Quick Google says that there was a service bulletin for the hands free link that was causing battery drain.
 
It goes to radio, door locks, and interior lights. Until I get this figured out, I am just going to pull the fuse. Don't need any of those features unless we are using this vehicle for a trip or something (rare).
I was gonna say as a short term fix wire a switch into it so you don't have to pull the fuse.
until you find it
 
Quick Google says that there was a service bulletin for the hands free link that was causing battery drain.
Edit i found it covers a 225-275 mA draw

Theres a LOT Of the TSB for that year model but i did find this...seams interesting

acur2.JPG
 
It's pissing an unreasonable amount of rain outside, if you don't find someone else I'll open the hood up on the wife's car when it's not like being underwater going outside.
 
Thanks for all the help so far everyone. This is by no means a super high priority as we have other vehicles to drive. I am out of town the next few days and will work on it again when I have some free time.
 
The most common cause for this is the Hands free link Control unit...you can just unplug the module and it will correct the problem without any other consequences other than loss of the function that the module provides. See the tsb 08-057.



The other thing we have seen is the a/c relay stuck on. You would see this at the a/c clutch...it would be pulled in all of the time. This normally will also cause freon to get pushed out to the blow off valve near the compressor. The relay is often labeled "MG". Key on engine off, if removing the relay and replacing causes the compressor clutch to "click" or pull in, the relay is stuck closed.
 
You leave the key in the ignition? For whatever reason if the key is in the ignition our TSX that era will die, but if we dont its ok. Been like that since we bought it 6 years ago.
 
As mentioned, it’s the Bluetooth module. Known common issue. It’s under passenger seat, unplug it
 
its not just that.

Fuse 4 is a 40a fuse right?

according the diagrams i have.

Fuse #4 of the underhood fuse panel is a 40a fuse and it feeds power to a bunch of shit. The wire coming from the the upper right of the sceen is coming out of fuse 4 after it also feeds fuse 8 for the VBU
acura mdx.JPG


Dont pay attention to the highlighted shit i didnt mean to do that

Quick Google says that there was a service bulletin for the hands free link that was causing battery drain.

The most common cause for this is the Hands free link Control unit...you can just unplug the module and it will correct the problem without any other consequences other than loss of the function that the module provides. See the tsb 08-057.



The other thing we have seen is the a/c relay stuck on. You would see this at the a/c clutch...it would be pulled in all of the time. This normally will also cause freon to get pushed out to the blow off valve near the compressor. The relay is often labeled "MG". Key on engine off, if removing the relay and replacing causes the compressor clutch to "click" or pull in, the relay is stuck closed.

As mentioned, it’s the Bluetooth module. Known common issue. It’s under passenger seat, unplug it

You all are correct! It ended up being the Bluetooth module. Thanks for the help! I was finally able to free up some time to work on this car last weekend (only almost a year later!). Replaced some HVAC actuators, put the battery tray and fuse box back together, (last time it killed a battery I shoved a larger battery in), replaced the battery with the correct size AGM battery, did some cleaning, and unplugged the Bluetooth module. Drove it yesterday and today and the battery drain issue is gone. Checked with a VOM and it is now only drawing 2-3 miliamps when in a resting state. Maybe with getting all these minor annoyances fixed, we might start driving this car more often. I don't see any negative side effects to having the Bluetooth module unplugged, so I think I will just leave it that way and forget about it. Thanks again!
 
Top Back Refresh