2001 c320 BATTERY DRAIN
01-07-2005, 12:34 AM
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2001 c320 BATTERY DRAIN
HI GUYS I seem to be having a problem with my c320. If left for 3 days the battery drains. I had brought it in to the dealer, they changed the battery, even had the wire harness changed, still nothing. I unplugged all the wires going to the seat, but nothing, still drains. The radio of the car goes on and functions but no sound comes out, do you think it can have something to do with that?? I disconnected all the wires from the radio yesterday and have been monitering the battery, and the voltage or amps have not dropped. Also, my srs light is on, and I get a fault "check coolant level" but the coolant level is fine! What should I do, do you think my amplifier is faulty, but when I took out just the Amplifier the battery drained as well. I had taken out the radio fuse and the battery drained as well. Its just weird, any ideas???
01-07-2005, 12:07 PM
#2
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Several things....
Search the forum and you'll find several things causing battery drain. One of them is the canbus not going to sleep and continually routing check sequences (or something like that). Seat motors and switches is another. If you find the canbus string it takes you through all that was done to check for the drain...and they checked A LOT of things.
01-07-2005, 09:10 PM
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I had a similar problem in my 2002 C240. You can read the thread here.
https://mbworld.org/forums/mercedes-tech-talk/91258-2001-c240-w203-canbus-draining-battery.html
In my case, unplugging the power seat controllers from both of the front passenger seats stopped the battery drain but at the cost of losing both power seats, the SRS system, and the adjustable steering wheel.
I hope your car is still under warranty so you can get it fixed at the dealer. My car is out of warranty so no free fix for me. Personally, I like to work on my own cars but find the W203 extremely frustrating because in my experience so far it seems that all the electronics are tied into the CANBUS network which cannot be diagnosed without the magic dealer laptop.
About your SRS light, were you perhaps playing with the fuses in the fuse box? When I was diagnosing my battery drain, I pulled each fuse out of the fuse box to look for the circuit that was draining the battery. Didn't find the circuit but did discover the hard way that pulling the fuse which provides power to the SRS system and turning the car on will cause the SRS lamp to stay lit until the dealer clears it with their magic laptop.
Just to add a little rant to the end of my post. What was Mercedes thinking by not adding some extra diagnostics to the car so the end user could fix minor problems themselves? Would it have killed them to just have the little malfunction display show the error code along with the malfunction message? It kills me that the computer in the car knows exactly what is wrong with the car but won't tell me not because it can't, but because Mercedes wants me to take the car to the dealer for every little problem. The trade-in value for the car is awful already and I think it's only going to get worse as more and more of the cars come off of warranty with problems which people feel are too expensive to get fixed.
Lawrence
https://mbworld.org/forums/mercedes-tech-talk/91258-2001-c240-w203-canbus-draining-battery.html
In my case, unplugging the power seat controllers from both of the front passenger seats stopped the battery drain but at the cost of losing both power seats, the SRS system, and the adjustable steering wheel.
I hope your car is still under warranty so you can get it fixed at the dealer. My car is out of warranty so no free fix for me. Personally, I like to work on my own cars but find the W203 extremely frustrating because in my experience so far it seems that all the electronics are tied into the CANBUS network which cannot be diagnosed without the magic dealer laptop.
About your SRS light, were you perhaps playing with the fuses in the fuse box? When I was diagnosing my battery drain, I pulled each fuse out of the fuse box to look for the circuit that was draining the battery. Didn't find the circuit but did discover the hard way that pulling the fuse which provides power to the SRS system and turning the car on will cause the SRS lamp to stay lit until the dealer clears it with their magic laptop.
Just to add a little rant to the end of my post. What was Mercedes thinking by not adding some extra diagnostics to the car so the end user could fix minor problems themselves? Would it have killed them to just have the little malfunction display show the error code along with the malfunction message? It kills me that the computer in the car knows exactly what is wrong with the car but won't tell me not because it can't, but because Mercedes wants me to take the car to the dealer for every little problem. The trade-in value for the car is awful already and I think it's only going to get worse as more and more of the cars come off of warranty with problems which people feel are too expensive to get fixed.
Lawrence
12-21-2008, 07:25 AM
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2002 C320 Wagon, 2008 E320 Bluetec Sedan
A late addition
I know this thread is over 1 year old but i thought I'd add my experience ... so if anyone is stuck on the road with an older model, they don't have to panic.
My 2002 C320 wagon also had battery drain problems when I was on a long trip. Problem was made worse because it was winter (-20C) and naturally reduced battery capacity.
The local MB dealer traced the problem to the driver's side seat position controller. The dealer didn't have necessary replacement part in stock and I didn't have time to wait for it to arrive so the temporary solution was to adjust the seat where I needed it and then pull out the seat module's fuse (fusebox located on the left side of the dash assembly - accessible when the driver's door is open).
Although it was inconvenient to not be able to adjust the seat while driving, it worked well to keep me going for another week until I got back home.
I don't know what part was actually replaced - the door unit or some other control module.
Regards to all.
My 2002 C320 wagon also had battery drain problems when I was on a long trip. Problem was made worse because it was winter (-20C) and naturally reduced battery capacity.
The local MB dealer traced the problem to the driver's side seat position controller. The dealer didn't have necessary replacement part in stock and I didn't have time to wait for it to arrive so the temporary solution was to adjust the seat where I needed it and then pull out the seat module's fuse (fusebox located on the left side of the dash assembly - accessible when the driver's door is open).
Although it was inconvenient to not be able to adjust the seat while driving, it worked well to keep me going for another week until I got back home.
I don't know what part was actually replaced - the door unit or some other control module.
Regards to all.
01-02-2009, 01:07 PM
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c240
C240 battery drain
I agree with Hackman. I am in the same boat as him. My 2002 C240 battery drained again (driver side seat control module last year) now draining again and MB wants $1000 again to replace the passenger side seat control module.
I am not going to fix it, and will do without passenger seat control. What a ripoff. MB should be held responsible for the seat control module issue but how is the problem.
I am not going to fix it, and will do without passenger seat control. What a ripoff. MB should be held responsible for the seat control module issue but how is the problem.
01-07-2009, 02:39 PM
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C320
I had a battery drainage problem on my 2002 C320 and I just got it back from the dealer. It was the passenger side seat control module that was causing the battery to drain its an expensive part to replace but at least my battery doesnt drain anymore and my passengers can adjust there seats.
01-11-2009, 02:27 AM
#7
There is a quick, easy, and free fix for this situation.
Basically, it works like this:
There is a plug going into the seat module with three wires...one brown, one red with a colored stripe (often green) and one black with a colored stripe (often white). The brown wire is the ground. The red stripped wire is the constant hot, and the black stripped wire is an accessory hot.
The red, constant hot is used to return the seat to the back and down position and move the steering wheel up and back (convenience entry function) when you remove the key and open the door.
If you don't mind getting rid of the convenience entry function the fix is quite simple. All you have to do is cut the red wire approximately three inches or so from the plug. Tape the end of the wire that runs up into the wiring harness off. Then, take the remaining red wire that runs into the plug and splice it into the black wire. Tape everything up and violia!
Basically, what you'll wind up with after this fix is a seat module that functions perfectly well. The only thing you are doing is converting the module to use two accessory hots as power, rather than one constant and one accessory hot. Again, the only functionality you will loose by giving up the constant hot is the convenience entry. This is because the seat will not move without the key in the ON position (which is when the accessory hots will become live).
Additionally all memory settings will be maintained as they are stored in the module without the requirement of a constant hot.
Let me note that I didn't think of this solution myself, I got it off another forum. But, I thought I'd let you all know that a solution does exist.
Basically, it works like this:
There is a plug going into the seat module with three wires...one brown, one red with a colored stripe (often green) and one black with a colored stripe (often white). The brown wire is the ground. The red stripped wire is the constant hot, and the black stripped wire is an accessory hot.
The red, constant hot is used to return the seat to the back and down position and move the steering wheel up and back (convenience entry function) when you remove the key and open the door.
If you don't mind getting rid of the convenience entry function the fix is quite simple. All you have to do is cut the red wire approximately three inches or so from the plug. Tape the end of the wire that runs up into the wiring harness off. Then, take the remaining red wire that runs into the plug and splice it into the black wire. Tape everything up and violia!
Basically, what you'll wind up with after this fix is a seat module that functions perfectly well. The only thing you are doing is converting the module to use two accessory hots as power, rather than one constant and one accessory hot. Again, the only functionality you will loose by giving up the constant hot is the convenience entry. This is because the seat will not move without the key in the ON position (which is when the accessory hots will become live).
Additionally all memory settings will be maintained as they are stored in the module without the requirement of a constant hot.
Let me note that I didn't think of this solution myself, I got it off another forum. But, I thought I'd let you all know that a solution does exist.
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03-03-2009, 04:10 PM
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Mercedes Wagon C320 '02
Battery drain problem 2002 C320
I wish I'd known about this forum two years ago. I had this problem and had it to the dealer several times but they just changed out the battery or thought I was nuts since it was intermittent. I'm the one that figured it out and made them change out the module because I suspected it (lots of deductions and note taking). Now I can go back and say "Toldja so." I just don't know why THEY didn't know how to fix the problem since the car was 3 - 4 yrs old when it happened. I'll know where to come if it happens again. Thanks for the "clip the red wire" info - could come in very handy.
Last edited by Mercedes Mom; 03-03-2009 at 04:12 PM. Reason: forgot something
04-29-2012, 01:16 PM
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2001 c240 mercedes
There is a quick, easy, and free fix for this situation.
Basically, it works like this:
There is a plug going into the seat module with three wires...one brown, one red with a colored stripe (often green) and one black with a colored stripe (often white). The brown wire is the ground. The red stripped wire is the constant hot, and the black stripped wire is an accessory hot.
The red, constant hot is used to return the seat to the back and down position and move the steering wheel up and back (convenience entry function) when you remove the key and open the door.
If you don't mind getting rid of the convenience entry function the fix is quite simple. All you have to do is cut the red wire approximately three inches or so from the plug. Tape the end of the wire that runs up into the wiring harness off. Then, take the remaining red wire that runs into the plug and splice it into the black wire. Tape everything up and violia!
Basically, what you'll wind up with after this fix is a seat module that functions perfectly well. The only thing you are doing is converting the module to use two accessory hots as power, rather than one constant and one accessory hot. Again, the only functionality you will loose by giving up the constant hot is the convenience entry. This is because the seat will not move without the key in the ON position (which is when the accessory hots will become live).
Additionally all memory settings will be maintained as they are stored in the module without the requirement of a constant hot.
Let me note that I didn't think of this solution myself, I got it off another forum. But, I thought I'd let you all know that a solution does exist.
Basically, it works like this:
There is a plug going into the seat module with three wires...one brown, one red with a colored stripe (often green) and one black with a colored stripe (often white). The brown wire is the ground. The red stripped wire is the constant hot, and the black stripped wire is an accessory hot.
The red, constant hot is used to return the seat to the back and down position and move the steering wheel up and back (convenience entry function) when you remove the key and open the door.
If you don't mind getting rid of the convenience entry function the fix is quite simple. All you have to do is cut the red wire approximately three inches or so from the plug. Tape the end of the wire that runs up into the wiring harness off. Then, take the remaining red wire that runs into the plug and splice it into the black wire. Tape everything up and violia!
Basically, what you'll wind up with after this fix is a seat module that functions perfectly well. The only thing you are doing is converting the module to use two accessory hots as power, rather than one constant and one accessory hot. Again, the only functionality you will loose by giving up the constant hot is the convenience entry. This is because the seat will not move without the key in the ON position (which is when the accessory hots will become live).
Additionally all memory settings will be maintained as they are stored in the module without the requirement of a constant hot.
Let me note that I didn't think of this solution myself, I got it off another forum. But, I thought I'd let you all know that a solution does exist.
12-18-2012, 09:06 AM
#11
REVIVE!!!
So I too have the passenger seat module issues on an '01 C320.
I did notice for a few months prior to this issue that the seat would occassionally refuse to go down...
Sometimes it would and sometimes it would feel like it was really straining to get the seat down...
Is this the motor or the module unit not relaying power to the motor?
So I too have the passenger seat module issues on an '01 C320.
I did notice for a few months prior to this issue that the seat would occassionally refuse to go down...
Sometimes it would and sometimes it would feel like it was really straining to get the seat down...
Is this the motor or the module unit not relaying power to the motor?
12-18-2012, 09:07 AM
#12
I took it to the dealer and the dealer finally diagnosed my module unit as being the draw.
Another weird thing, sometimes when I would recline the seat down... the headrest would go up...
Another weird thing, sometimes when I would recline the seat down... the headrest would go up...
01-07-2013, 06:09 PM
#13
I agree with Hackman. I am in the same boat as him. My 2002 C240 battery drained again (driver side seat control module last year) now draining again and MB wants $1000 again to replace the passenger side seat control module.
I am not going to fix it, and will do without passenger seat control. What a ripoff. MB should be held responsible for the seat control module issue but how is the problem.
I am not going to fix it, and will do without passenger seat control. What a ripoff. MB should be held responsible for the seat control module issue but how is the problem.
The Passenger seat control modul cost $270 on line , easy to replace . good luck .
01-08-2013, 06:19 PM
#14
I just replaced both seat modules myself. Took me 5 min each. No screws to remove only 6 cables each.
Bought from amazon for 200 each Shipped!
Stupid dealership gave me an invoice for 900 EACH! I said some profane words to them in my mind and left.
Bought from amazon for 200 each Shipped!
Stupid dealership gave me an invoice for 900 EACH! I said some profane words to them in my mind and left.
