2009 C220 CDI (W204) - slow battery drain (3 days plus)

[mossy]

hi, I am having this problem on my car - If I don't drive anywhere for 3 days the car will not have enough juice to start
radio etc will come on so the battery is not fully flat

I did some testing today with a DVM, made sure the door latches were closed and also the boot latch (the battery is in the boot in my car)
When I connect the dvm to the negative cable and thus complete the circuit, there are some sparks which I guess is normal. I noticed however that at that point the amperage reading spikes to about 3A, stays there for about 2-3 seconds and then eventually drops to around 150mA - a relay can also be heard switching in the boot fuse box location

However, leaving everything connected the meter hangs around 150mA - would this be enough to cause a starting issue in 3 days? I checked the current battery voltage and it's around 11.95V, alternator output around 13.9 -14V

I pulled all the fuses in the boot section 1 by 1, then went to the under the bonnet driver's side - I did find 1 fuse there, fuse 27 (7.5A), which when removed dropped the current reading down to about 75mA.
From the documentation I have here, fuse 27 is listed under the following functions
Engine Electronics
Fuel Pump
Ignition Lock
Starter
Steering Lock

One thing I could not locate was the 3rd fuse box, I took off both side panels on drivers' side and then passenger side but could not see it, does anyone know another location for this? thank you for any help

 

[richard]

150ma constant draw = 3.6A per 24 hours, so probably wont be a killer in 3 days (you'll have lost 11A of capacity). However, it should be lower really after the car has gone to sleep (some minutes after locked) - how long did you leave it. The EIS is on that fuse, and that controls lots of stuff, so not surprised by that drop when removing the fuse, especially if car wasn't completely asleep.

Have you had the battery fully tested ? And what's the date stamp on the top of one of the battery posts ? Its week/year, so if more that 3 or 4 years old, it could well be dying

 

[mossy]

150ma constant draw = 3.6A per 24 hours, so probably wont be a killer in 3 days (you'll have lost 11A of capacity). However, it should be lower really after the car has gone to sleep (some minutes after locked) - how long did you leave it. The EIS is on that fuse, and that controls lots of stuff, so not surprised by that drop when removing the fuse, especially if car wasn't completely asleep.

Have you had the battery fully tested ? And what's the date stamp on the top of one of the battery posts ? Its week/year, so if more that 3 or 4 years old, it could well be dying

Thanks richard - ideally it would be lower yes but it appears something is draining the battery when it shouldn't be - the car was off for about an hour or more. The other possibility is an intermittent draw I'm not seeing
I got a new battery installed last year just to rule it out
I checked the voltage on the battery this morning before starting her up, read about 11.9V - mechanic says it should be around 12.2, I'm not sure what the threshold voltage is in order for the car to turn over but 11.9V is ok

 

[Petrol Pete]

I have posted this vid a number of times . Apologies if you have already see in .

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[mossy]

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yeah I have watched that one it's very good, thanks

 

[mossy]

I went back at this again to ensure I had left the car sitting for long enough, i closed the door latches and boot latch and left it for about 90 mins with the multimeter connected in series
The reading was consistently about 166mA with occasional spikes to about 200mA ish

I could not find the cockpit fuse box (the one that's supposed to be beside the light switch) - according to the fuse layout sheet there are only 5 fuses in it anyway, 2 of which it says are the Seat Adjustment, front. I disconnected the power and signal cables from the front seats but this did not change the read out

If I do ever happen to find this drain i'll report back here but for now I will just have to make sure the car is driven every couple of days

 

[Smiley]

Or you could leave a trickle charger on it.

 

[Mbc1802007]

I went back at this again to ensure I had left the car sitting for long enough, i closed the door latches and boot latch and left it for about 90 mins with the multimeter connected in series
The reading was consistently about 166mA with occasional spikes to about 200mA ish

I could not find the cockpit fuse box (the one that's supposed to be beside the light switch) - according to the fuse layout sheet there are only 5 fuses in it anyway, 2 of which it says are the Seat Adjustment, front. I disconnected the power and signal cables from the front seats but this did not change the read out

If I do ever happen to find this drain i'll report back here but for now I will just have to make sure the car is driven every couple of days

Hi Mossy! Any updates on this one?

 

[mossy]

Hi Mossy! Any updates on this one?

Hi, no, no updates, I had to give up on it
I did find a a fuse that, when pulled, the current draw dropped by half, the problem is there are 4 or 5 things running off this fuse so it didn't narrow it down really, I just make sure I run the car every 2 days and it's fine

 

[krzyszf]

Hi
It looks like we have an identical problem with our car. Looking at the attached file, the repair seems simple. I have already checked everything I could, in turn disconnecting the modules given on fuse 27 and nothing, then current consumption 0.12 and no system sleep. I still had to disconnect the ignition switch (I have already disconnected the immobilizer bolt under the steering wheel) and the starter, but it is very difficult to access.
Maybe you came up with some solution?

 

[krzyszf]

One thing I could not locate was the 3rd fuse box, I took off both side panels on drivers' side and then passenger side but could not see it, does anyone know

another location for this?

If you are looking for a 3rd box (F34), I put a photo, but not everyone has it, depending on the equipment (seat memory, heating, etc.)

 

[mossy]

Hi
It looks like we have an identical problem with our car. Looking at the attached file, the repair seems simple. I have already checked everything I could, in turn disconnecting the modules given on fuse 27 and nothing, then current consumption 0.12 and no system sleep. I still had to disconnect the ignition switch (I have already disconnected the immobilizer bolt under the steering wheel) and the starter, but it is very difficult to access.
Maybe you came up with some solution?

hi krzyszf - which attached file are you referring to?
I gave up on this issue, I plan to change the car early next year
thanks

 

[krzyszf]

which attached file are you referring to?

Photo of the arrangement of fuse boxes

 

[mossy]

Photo of the arrangement of fuse boxes

ah ok, my apologies
i think for the fusebox i was unable to find there weren't many fuses actually at all in said box, i think maybe the seat motors fuses are in there - instead I just disconnected at the seat motor plugs, however this did not seem to reduce the current draw

 

[Wild]

Same problem with my car. Strange you say that fuse is connected to Ignition lock and Electric Steering Lock (ESL). The key has sometimes been very hot plus the motor in the ESL had lost its carbon brushes and I had to pull the steering column out to cut the ESL off. I could not fix it with a new motor from China (US$4), so I had to send it to Australian ECU Service and got it fixed for $450.

Been told that the ignition switch really only handles small currents, so it should not get hot??

Have disconnected all six connectors to front seats and still have a parasitic draw, Swings from 66 to 70 mAmps, but occasionally goes up to 200 mA - too much. Also 6mA very occasionally with boot open.

One suggestion is to put a 200 Amp relay into the circuit from the battery and drive that relay from the ignition switch. Any other suggestions? I am still testing.

One mechanic said one client had to pay $4,000 a few weeks after warranty expiry at a Merec stealership to fix the draw from some "utility", but he did not say which one.

 

[mossy]

Same problem with my car. Strange you say that fuse is connected to Ignition lock and Electric Steering Lock (ESL). The key has sometimes been very hot plus the motor in the ESL had lost its carbon brushes and I had to pull the steering column out to cut the ESL off. I could not fix it with a new motor from China (US$4), so I had to send it to Australian ECU Service and got it fixed for $450.

Been told that the ignition switch really only handles small currents, so it should not get hot??

Have disconnected all six connectors to front seats and still have a parasitic draw, Swings from 66 to 70 mAmps, but occasionally goes up to 200 mA - too much. Also 6mA very occasionally with boot open.

One suggestion is to put a 200 Amp relay into the circuit from the battery and drive that relay from the ignition switch. Any other suggestions? I am still testing.

One mechanic said one client had to pay $4,000 a few weeks after warranty expiry at a Merec stealership to fix the draw from some "utility", but he did not say which one.

I dunno, my gut feeling is that one of my SAMs are faulty but selling the car soon so not willing to spend a fortune trying to fix it. The ignition switch thing sounds weird on yours though

 

[mossy]

Update: issue has deteriorated, drain has increased such that the car won't start after about 10 hours. Even with the battery disconnected over night it would not start this morning. There is some juice in the battery but doesn't seem to be enough, luckily i bought a battery pack so I can start it
Bringing it to local mechanic soon and hopefully he can find whatever is draining or what the problem is, will report back

 

[mossy]

Looks like the battery has died, have another battery in there and the car is starting ok again - maybe the parasitic draw has damaged the battery over time, only 2 years old, Yuasa