170 milliamp draw
all modern cars eat power with the thing's locked, alarms and can bus electronics doing strange stuff, what about keyless ? do the antenna's seeking out the key stay awake, don't see how the car can detect it otherwise? its why I wrote it should cope for three week's doing nothing, after that its always a gamble on any car post 1994. Some can't do 2 weeks, its why daily drivers have less issues
Last edited by BOTUS; Mar 14, 2020 at 04:29 AM.
the keyless stuff in the doors are another designed to fail headache, they stop things locking and many owners never notice, not sure if it drains current
if you can't wipe out faults its possible things are in a muddle and don't shutdown due to noise on the can bus. In earlier ones (S SL or CL) you should never disconnect a battery without nearly dealer level diagnostics or it'll never be happy (and if you have the "standard" damp puddle under the passenger footwell carpet you can spend 3 months on these fighting and get nowhere - till you resolve the damp and corroded connections).
The electrics are much better on the 221 and disconnecting the battery is OK, and I'm not sure if leaving faults there can cause an issue, but it would likely give you a clue as to what is playing up to look. depending upon spec you can have 56 modules complaining about nothing. If you don't have gear that can talk to all these modules then you should probably hand to someone who has, although you might get lucky. If its keyless I'd start there
Last edited by BOTUS; Mar 16, 2020 at 01:55 PM.
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The series of events that lead up to this problem was that I drained the battery by having the ignition on for 2 hours without engine running, then I put in a Walmart battery I had sitting for 4 months and it would be at 11.5 volts after a day, so I put in a new autozone battery and after a day it was at 5 volts I got 2 other ones from warrant and they did the same thing. I've seen it go to 20 millivolts and stay but then I ran the test a few more times and it will only go down to 170 millivolts. Do I have to unplug the seat module to see if it's the problem or will pulling the seat adjustment fuses do the same thing?
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the keyless stuff in the doors are another designed to fail headache, they stop things locking and many owners never notice, not sure if it drains current
if you can't wipe out faults its possible things are in a muddle and don't shutdown due to noise on the can bus. In earlier ones (S SL or CL) you should never disconnect a battery without nearly dealer level diagnostics or it'll never be happy (and if you have the "standard" damp puddle under the passenger footwell carpet you can spend 3 months on these fighting and get nowhere - till you resolve the damp and corroded connections).
The electrics are much better on the 221 and disconnecting the battery is OK, and I'm not sure if leaving faults there can cause an issue, but it would likely give you a clue as to what is playing up to look. depending upon spec you can have 56 modules complaining about nothing. If you don't have gear that can talk to all these modules then you should probably hand to someone who has, although you might get lucky. If its keyless I'd start there
around Europe MB enthusiasts all have good stuff to say about icarsoft MB||,
but in the modern world that still leaves you short of flashing the right software due to merc SCN headache. Where its a 3k USD for something decent like Autel's new MS908S Pro or the online xentry toy at 12k a year rental and only works on Mercs.
Last edited by BOTUS; Mar 18, 2020 at 01:18 PM.









