I've got a 2007 Accord EX V6 that I can't seem to narrow down the parasitic drain on. Car has 205k miles and I just had the timing belt replaced back in July of 2020. This was the most recent service work. About two months ago, the battery started to die randomly. I would jump it, get it running and everything would be fine, then it would be dead 2-3 days later.

After getting it jumped again, checked voltage (engine off) and had 13.2VDC. Turned vehicle on, and disconnected + cable from battery to check the alternator. Alternator was putting out 14VDC. Decided to replace the battery. Well, wouldn't you know it, about a week later it's dead again. So now I know I've got bigger issues. Set the car on a trickle charge to get it back to "full". When in Sleep mode, I checked the current draw by disconnecting the - battery terminal and placing my VOM in series. When I initially connect the - VOM lead to the - battery post, I get an inrush of .5amps(500mA). It quickly drops to .150(150mA) and stays there constantly. I tried pulling all of the fuses and relays from under the hood, and the fuse panel on the drivers side. When I pull the fuse 23 (+B IG1 and Power Windows), the amperage drops to .030(30mA). I've narrowed it down to something on the B-CAN link, but not sure where to start or what all is actually on the link. As an additional test, I unwired the + terminal off of the alternator to see if I was getting some leakage there but no change. The only fuse that changes the Sleep MODE amperage draw is fuse 23.

 

Does your car have a hands-free bluetooth device? If so, it is most likely the same unit used in the 3G Acura TL, and widely known to cause parasitic draw.

 

1. Does the car have any electronic Honda accessories added such as XM Radio?

2. Since pulling the under-hood no. 23 multi-fuse (50/50) drops the amperage. Try pulling under-dash Fuse No. 27 (20A) for the power window master switch. The door multiplex control unit which is incorporated into the driver power window master switch is part of the B-CAN Communication Line circuit.

 

Thank you both for the replies.
No, the vehicle does not have a hands-free bluetooth device of any kind.
Nothing has been added, but it does have Navigation option. When I pulled the fuses under dash, no fuse made any chage in the draw. I used a piece of 2x4 and a clamp to hold the door switch in to keep the car in sleep mode when I was testing.
The only fuse that has made a difference is the under hood 23.

 

had similar problem on my '04 - https://www.hondaaccordforum.com/for...e2/#post396807

V6 - a similar thread https://honda-tech.com/forums/honda-...drain-3196780/

get this tool - DTC tool (07WAZ-001010A) (only online from Honda dealers ~ $15 + $20 ship)
see the non-HDS DTC process in Service Manual pages 22-96... it's a bit tedious - there are multiple subsequent tests to (maybe) isolate the specific cause,
- you have to pull off the left kick panel to get at the port for the tool

or - take car to dealer & have 'em plug in the HDS analyzer

 

Following . . .
My 07 accord 4cyl auto, 4 door has had very similar problem since I bought it. Bought the car new in April 2007. The first winter, 2008 the battery would die slowly when the outdoor temps are below about 40. Took it to the dealer *many* times. They put the car on their computer and said "nothing wrong". So bad, I took my family on a ski trip in new Hampshire, the battery dies so fast I had to get up in the night to start the car so it would run the next morning. Dealer: useless. Changed battery 4x over the past 15 years. I have just about no options on this car.

 

Does the battery drain when temperatures are above 40?

 

its weird. When its warm out, it cranks slower if I leave the car sit for days, but it starts. I haven't had the battery go almost dead at higher temps. When its colder, below freezing, winter here in MA, much worse. Dealer checked several times, I

 

Another thing to consider is the positive battery cable; many mid-2000s Honda and Acura models, specifically the Accord and TL here (which share a platform and are built on the same assembly line), have had strange issues with the cable; in the case of my 2006 TL, if I didn't start the car for a few days the starter would barely be able to crank the engine, and thinking it was the battery, I replaced it. The problem seemed solved for a few months and then it popped up again; fortunately my car has a manual transmission, so I'd simple put it in reverse, take the parking brake off and roll the car a few feet down the hill before popping the clutch, and for the next several days, no starting problem. One day I happened to wiggle the battery cable (not the end but the cable as it went into the post clamp), and the problem went away for a month or more; the next time the issue popped up, I did the same thing, with the same results. I bought a new battery cable and for the last two years, not an issue.

 

The current draw may be smaller during warmer temperatures. If you have a volt meter that can read amperage, then you can measure the current used when the vehicle is off.

Search for Battery-Alternator-Draw Tests: EASY & ACCURATE on youtube. A long detailed video that my be worth watching. More importantly, at 23 mins, he shows how to measure amps using a volt meter.

Make sure that the car is asleep with doors shut, lights off, etc. If you open your car door and the dome light turns on, you will likely blow the fuse in the volt meter. I've seen people use a clamp on the driver's door to hold in the door switch, so they can access the interior fuse box for testing. Some cars take over 45 minutes to go to sleep, so I suggest that you connect the volt meter and watch the amp draw. Come back in an hour to see if the amp draw (If any) is the same. 15-20 milliamps (0.015-0.020 amps) is normal for current draw. Anything greater will require some diagnostics.

Post what current draw you measure. If excessive, you can either use another volt meter to test the fuses, or you can start pulling fuses one at a time to see what fuse/circuit is drawing the current to narrow down the problem.