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Crazy phantom battery drain ?

geoffdragon said:
That drain does look low. Don't know whats on your car but mine has all the toys.
Click to expand...
so does mine ....satnav, dual climate control, leather seats, tailgate, sun roof, reversing sensors, etc, etc
 
Thats interesting, you must be the lucky one. LOL
Just spoken with the service manager ( who used to be a tech ) for about 10 mins at Bassets Honda Swansea.
Explained everything to him, The maximum drain shown on their computer system is 30ma.
He said he had come across similar problems and the main culprit is the micu unit.
Over the years they have changed about 40 of them, many under warranty and goodwill, but that wouldnt be the case here.
There is no way of testing other than substituting it for a known good one.
He suggested pulling the underbonnet fuses to find the circuit, using the Wattmeter to see if current draw stops fluctuating.
He then went to talk with the workshop and on a recent occasion the fault was the alarm siren.
He suggested disconnecting that to try.
So basically if the car went in to them, they would do everything I have done, then start replacing parts until the problem is cured.
I think the way forward now is to disconnect the alarm siren first, then start pulling fuses and finally think about the micu/fusebox.
 
Hi, yes a manual would be useful. I'll have a look later.
I have established the siren is on the drivers side of the boot. Had a quick look and theres a load of poppers and rubber trim to move to get at it.
Have to go out later so no time now.
Just as a matter of interest regarding the fluctuating amps reading.
I tried the wattmeter on the car with it open - same result.
Pulled fuse 7 in car ( I think thats the MICU fuse, as well as other things ) - same result.
Read elsewhere that when the lithium battery on the siren goes, it is constantly trying to recharge itself.
I really hope thats the culprit, but this fluctuation is wierd.
Will also have a look for a 1 ohm fuse, I would think a 100 watt one would do.

Does that manual cover the diesel ?
Yes it does. Found the link now.
 
yes I've had a look on the DVD, the siren is behind the offside boot trim (from the DVD it doesn't look easy to remove the trim). But you never know, maybe there's a built-in charger in the siren that causes an oscillating current drain.

re "Will also have a look for a 1 ohm fuse, I would think a 100 watt one would do"...... if "fuse" is a typo and you mean a 1 ohm resistor (so that you can use the scope), it doesn't need to be 100 Watt because there's only 100 mA going through it, so 1 Ohm 1 Watt will be ok (which will carry a constant 1 Amp, anything more than 1 Amp is transient, and anyway it might be a good idea to put a jumper-cable in parallel to begin with, just so that the car gets max Volts initially).
 
Thanks. The guy who fitted the reverse sensors took 5 minutes to get the trim off. So it can't be that difficult. Lol.
Yes typo error. Resistor.
Sorry, heads going now. Need to calm down and think logically.
 
Just checked the alarm again. Hand I through window alarm set off loud. Remember alarm went off last week when disconnecting battery. ( must have locked up before doing that ) and it was very quiet. Sounds like the battery in the siren is giving up ghost. We shall see.
 
if you do take it out and you can take it apart, take some pics of the battery and charging system (if there is one)

one point though ...when the internal battery of an alarm siren is near its end of life, if the main power source is removed and then the internal battery volts drop (because the internal battery is near its end of life), the siren usually starts to sound even when not set (because the siren thinks that someone has cut the main power source and is tampering with the siren)
 
Point taken. I hope it will be ok to disconnect without the alarm set then check to see if the current fluctuation goes away. That's why I tried earlier to see if it was still there with the car unlocked.
 
yeah it could well be the siren, seems a good bet, I'm just puzzled why it's behaving itself when there are symptoms of the internal battery being almost dead
 
I guess it's because it's connected to the car battery virtually all the time. No idea how it's supposed to charge but there must be a voltage dropper/ regulator built in. Really hope it's this trying to charge and wobbling the current drain. It's got to be first on the list.
 
Hi. Nice day so here we go again. Took the alarm siren off and measured draw. Slightly lower at 122ma total in an hour. Amps still fluctuating 0.00 to 0.13. While it was off I took it apart - very easy, two screws. Battery pack is 6 button cells soldered together, connected to pcb with computer type connector. Anyway they show 6.42v. Rated at 7.2v so not too bad. Disconnected reverse sensor as well - no difference. When I put it all back together - before locking up I noticed the spot amps had fallen, so going to watch that for a while before diving under the dash to try to see a part number on the fusebox/micu
 
On Tuesday I thought I better test my alarm and it works ok.

So I reset the Watt-meter and it's been running for 50 hours, and it now reads 0.465 Ah
That means that the current drain should be as low as 9.3 mA with the alarm set.

If I were you, I would get everything working properly in the car, it could be that the MICU does not shut down until it has "heard" from every device on the B-CAN.
 
Boy oh boy, I'm dreaming of those sort of numbers. Checked the fuses again and the only one that drops the drain right down is fuse 7 under the dash. From the list I have that supplies combination switch control, guage control, immobiliser control receiver, immoes control unit ?, navi display, navi unit, tailgate control, ultrasonics, alarm siren and micu. How do I check all those ? I guess taking the navi and radio out of circuit is an option, though I don't know how much work involved.
As far as I'm aware, everything on the car is working as it should.
Managed to get at fuse box and using a mirror and phone camera, get the part numbers. How much of the numbers I would need to match is a mystery.
The main numbers are sef-e13 ce1, ce1pvp63, and 020305 which I think is a date. The number embossed on the front is pp gf15 m3. Apart from space restriction it doesn't look to bad, as most of the plugs are multplugs. All different shapes. Don't know wether to look elsewhere before diving in there.
 
Maybe unplug some of the bits on fuse 7, if you want to make life easier to get fuse lists and locations, get an e-manual/DVD
http://typeaccord.co.uk/forum/topic/19784-uk-service-manuals/

If you want part numbers, best to start here http://www.lingshondaparts.com/honda_car_parts_catalogue_C01.php

you can either put in the car reg or VIN, or if you don't want to do that just start in the "choose by model"
I did the latter and went for Accord, 2005, UK, 2.2, Executive ....you should end up with a load of thumbnails to wade through
http://www.lingshondaparts.com/honda_car_parts_block_selection_C30.php?mod_01=2946

Control Unit (Cabin) gives this page
http://www.lingshondaparts.com/honda_car_parts_selection_pfk.php?block_01=17SEA01&block_02=B__1313&block_03=2946

if you delete "_pfk" from the url you get the same page but with proper Honda part numbers
http://www.lingshondaparts.com/honda_car_parts_selection.php?block_01=17SEA01&block_02=B__1313&block_03=2946
 
Hi. Had a busy afternoon. Thought I'd start disconnecting bits as you suggested. Had the satnav out and radio with display but no change. Also found a parrot Bluetooth unit have removed that and all the wiring that went to it. Don't know who put that in but wires were tucked into radio plugs. Again no difference. Well that's a couple of the connected bits checked.
I have the lings site bookmarked but thanks for the tip about honda part numbers. Have messaged the guy about a service manual but no reply as yet. Maybe I'll have to ring him. Any idea what the "immoes control unit" is ?
It's pointing more and more at the fuse box isn't it.
Also unplugged the power boot lock - no change
 
AFAIK the IMOES is something to do with the RFID in the key (no idea what IMOES actually stands for)

Regarding that Parrot Bluetooth wiring, HFT kits are known to cause battery drains and I don't think anyone ever found out why. If one was wired in and then removed, it might be that wiring that has somehow caused the problem. I guess it depends where the wires went and what had been done to the original wiring to insert the kit into the system. If I were you I'd thoroughly check all the wiring, there may well be something that has not been put back properly and is affecting the MICU ?
 
I disconnected all the unit connections and removed the wires from the radio. There was a relay that I removed together with the wiring right back to where it joined into the car loom. It's such a jumble under the dvd unit, I think the srs unit is there and it had a maze of wires. Wondering whether to try the tin foil trick of seeing if there are any error codes in the micu. Don't think there's any more I can unplug from fuse 7. Maybe time to try to get hold of another fusebox.
I had a look at the parrot installation instructions and am pretty sure I got all the connections even if I couldn't get all its loom out.
 
well there are 3 possibilities

1. the current micu went faulty when the HFT kit was installed and it's now causing the drain
2. the current micu is causing the drain because of something wrong with the wiring and a replacement will do the same
3. it's not the micu

btw, did you ever get any DTC's on the OBD port ?
 
Don't really know what to think now. Given that I have disconnected as much as I can from fuse 7 I wonder if just disconnecting is enough or does there need to be a substitution of each module. I take your point about the wiring but don't know what else can be done other than removing the add ons and the wiring. Given my conversation with honda it does seem that the micu is a weakness in the system and that replacement is the only test, I think I'll try getting one off the bay. I know that's taking a chance but I'm not going down the honda price route at this stage. I have seen some photos of a dismantled one and the corrosion was horrendous. May try to see if there are any fault codes in the micu over the weekend.
 
If you're plugging a reader into the OBD port already, then I don't understand what you mean by "May try to see if there are any fault codes in the micu over the weekend". An OBD reader will give you any codes for any module (the modules all report their codes), although an HDS (or a very expensive generic diagnostic system) might show up something that a cheap reader/scanner won't.

On the Honda e-manual/DVD there is an extensive procedure for electrically testing the MICU ....as I say,you might get another MICU from ebay, plug it in, and find the same problem, thereby asking yourself if you now have 2 faulty MICU's or a wiring problem. Same could be true even if you get a brand new one from Honda (which is unnecessary).

Also, the battery in my car definitely used to go flat if left locked for several weeks (alarm on obviously), but looking at that Watt meter, that is not the case any more. I have no idea why it did, nor why it stopped.
 
Hi. There is a test socket on the fusebox to take a plug that shorts the two pins in the socket. Any error codes in the can bus are displayed on the odometer. If more than one they can be cycled through with the odo set button. Decoding the codes may throw some light on the problem. I picked this info up on the civic forum. Also got a honda printout on it. Have ordered a manual and a fusebox, so waiting for them now.
 
That's the "SCS connector", all it does is force DTC's to be displayed on the instrument panel, AFAIK you'll get nothing different from the data you get using a decent OBD reader/scanner, or definitely with an HDS or suitable generic diagnostic system.
 
Your right, I got excited when I saw it. LOL
Shows DTC's without a reader.
Anyway I'm commited now to try changing fuse box. If it doesn't work I have no idea where to go next - just make sure the car gets used every few days and suffer the Passat to go away.
If the weather dries up later, I'll connect the O'scope and have a look at the output variation pattern of the milliamps ( had a couple of 1 ohm resistors in the post ).
Don't know if it will prove anything new but it should look pretty.
Came across a "car reliability survey" on the net yesterday and Honda are top of the list. However, it also said that 33% of breakdowns/repairs accross all manufacturers are electrically related.
Bring back the magneto and dynamo.
 
Checked the resistance of the 1 ohm resistors and they are bang on 1 ohm.
Have measured the drain using the 1 ohm resistor and the DIGITAL MM and oscilloscope using mv as ma.
Conected the DMM up first to get an idea and not to risk my o'scope. Fluctuating between 22 and 48 ma.
Connected o'scope and after playing with mv and time scales get readings showing 21ma for 4 seconds going to 50ma for 600ms, then back to 21ma. The maximum reading was 50ma.
Reconnected the Wattmeter and it shows 126ma draw in an hour, peaking at a 150ma spot reading.
How do I reconcile these tests ?
 
Just spent an hour removing the Parrot wiring, and found what I think is a "mute" box.
The wiring had been cut going into the SRS control box, looping into the Parrot module and then back to the SRS box.
Wonderful sparky did that job, all connections crimped.
I've removed it all and repaired the original loom. So thats gone.
Still no difference in the Wattmeter readings.

I'm ***uming its the SRS unit. Its a black box with 2 plugs in the side of it, bolted to bracket below the satnav dvd unit, in front of the ashtray.
Anyone confirm ?

Or it could be the ECM/PCM ? Whatever that is.

Sweat over, it's the premium sound system amplifier ***embly.
 
I was parked in my 2.4 tourer for 25minutes with the radio on and killed the battery!!! (Apologies for it being slightly unrelated)
 
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