battery drain

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chaders205

New Member
Joined
Apr 16, 2021
Messages
2
Location
morecambe
Car
220cdi 07 / slk 200 05
hi had this 220cdi for 7 months no problems at all till yesterday
car started in the morning went to work 4 miles came home at lunch got back in the car battery allmost flat
so used wifes car for work came home battery completely flat nothing on in the car as for as i can see
removed battery charged it over night started first time went to work 1/2 hour later allmost flat again
changed the battery for another one car started fine 1 hour later completely flat
 
How old is the battery?
Possible engine block heater short circuit?
 
did a diognostics with carsoft all it came up with was lo voltage and low gas pres on the aircon
charged the battery again and wait to see if it go's down
 
Get an ammeter and measure the current draw. If it is high then start removing fuses one at a time to find the circuit that is causing the drain.
 
The technical term is Battery knackered
 
I had a similar problem as you. Mines was the seat module. Tested by removing the fuse in driver side fuse panel
 
Hi,

I wonder if someone could help with battery parasitic draw on a W211 E320 2006. I have a brand new battery and have noticed over the past year or so, that their appears to be parasitic draw and so I have been recently checking the new battery (2 weeks old, type 019 AGM) as I want it to last a long time. Before putting the battery on the car, I checked the voltage which was 12.63V. Leaving the battery connected overnight, the voltage drops to around 12.1V-12.2V. I ran the car and the alternator took the battery to about 14.4V (the auxiliary battery was 12.4V and about 14.4V with the alternator).

After charging (leaving the car running for a while) to about 12.5-12.6V, I carried out a parasitic draw test and got 135mA. I removed each fuse in turn and the figure stayed constant. I removed each relay in turn and still the figure was constant at about 135mA.

I understand that generally the maximum draw that I should get is about 50mA, and ideally less than that figure. I was careful to clamp off door locks so that all lights were out and waited an extra while to make sure nothing apparent was drawing current before I carried out the test.

Later, I carried out a diagnostic test and got the error message '930E synchronization of the DTC memory cannot be ensured' - a message that I have seen before, but despite past deletions of this message it still seems to be coming back. This message coupled with the high figure for the current draw leads me to believe that their is a problem with the vehicle, so if anybody can help, I'd appreciate it!
 
I had a similar problem as you. Mines was the seat module. Tested by removing the fuse in driver side fuse panel
if i had a seat module fault also does anyone on here know of someone to look at or replace cheers
 
Hi,

I wonder if someone could help with battery parasitic draw on a W211 E320 2006. I have a brand new battery and have noticed over the past year or so, that their appears to be parasitic draw and so I have been recently checking the new battery (2 weeks old, type 019 AGM) as I want it to last a long time. Before putting the battery on the car, I checked the voltage which was 12.63V. Leaving the battery connected overnight, the voltage drops to around 12.1V-12.2V. I ran the car and the alternator took the battery to about 14.4V (the auxiliary battery was 12.4V and about 14.4V with the alternator).

After charging (leaving the car running for a while) to about 12.5-12.6V, I carried out a parasitic draw test and got 135mA. I removed each fuse in turn and the figure stayed constant. I removed each relay in turn and still the figure was constant at about 135mA.

I understand that generally the maximum draw that I should get is about 50mA, and ideally less than that figure. I was careful to clamp off door locks so that all lights were out and waited an extra while to make sure nothing apparent was drawing current before I carried out the test.

Later, I carried out a diagnostic test and got the error message '930E synchronization of the DTC memory cannot be ensured' - a message that I have seen before, but despite past deletions of this message it still seems to be coming back. This message coupled with the high figure for the current draw leads me to believe that their is a problem with the vehicle, so if anybody can help, I'd appreciate it!
Hi there, I’ve spent most of the day trying to find out where my battery draw is coming from, I still need to do more testing but I’m almost sure it’s coming from the passenger seat module, I missed it first time as it seams to take an age to go to sleep. I’ve heard you can somehow alter wiring to module so that it’s only active when the ignition is on, or it’s a used or new module, I’ve just removed fuse for time being. I did have trouble starting car when I reinstalled battery after overnight (battery was around 12.1, and has never not started) charging, car would crank strong but not fire, I sought advice and I was told it could be fuel pump, although I had not touched those fuses, but I had a riffle round and looked at fuse which was missing plastic protective cover and black tape to secure, anyway car fired up after the riffle round, must be something loose disturbed by myself whilst moving battery around. I was meant to be taking my girls to the train station, but they had to get a taxi in the end, dog house again.
 
Hi there, I’ve spent most of the day trying to find out where my battery draw is coming from, I still need to do more testing but I’m almost sure it’s coming from the passenger seat module, I missed it first time as it seams to take an age to go to sleep. I’ve heard you can somehow alter wiring to module so that it’s only active when the ignition is on, or it’s a used or new module, I’ve just removed fuse for time being. I did have trouble starting car when I reinstalled battery after overnight (battery was around 12.1, and has never not started) charging, car would crank strong but not fire, I sought advice and I was told it could be fuel pump, although I had not touched those fuses, but I had a riffle round and looked at fuse which was missing plastic protective cover and black tape to secure, anyway car fired up after the riffle round, must be something loose disturbed by myself whilst moving battery around. I was meant to be taking my girls to the train station, but they had to get a taxi in the end, dog house again.


if i had a seat module fault also does anyone on here know of someone to look at or replace cheers


Yes, so I also had this "Fix" done to mine where the live wire is basically cut, so the seats only move when ignition is on.

I believe, to replace the seat module is around £400-£500 as the module is a bit expensive, but also needs to be programmed on STAR's so it knows what each button does. I just had the "Fix" done by PCS for a considerably less amount.
 

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