Still having low battery convinience functions unavailabile, please help
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Joined: Aug 2024
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W211 E320
Still having low battery convinience functions unavailabile, please help
I recently purchased a 2005 W211 E320. After driving for a day, I am getting a ‘low battery convenience functions unavailable’ error.
I have checked the battery in the trunk, the small battery, and the alternator. Both AutoZone and the dealership confirmed that they are fine.
I replaced the auxiliary battery module as well, but I am still getting this error. However, it goes away after driving for a while. Does anybody have any suggestions?
I have checked the battery in the trunk, the small battery, and the alternator. Both AutoZone and the dealership confirmed that they are fine.
I replaced the auxiliary battery module as well, but I am still getting this error. However, it goes away after driving for a while. Does anybody have any suggestions?
MBWorld Fanatic!
Joined: May 2017
Posts: 2,290
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C320
The wiring harness battery terminals at the main battery in the back can become oversized and loose. Remove the terminals, clean them and retighten, then try to wiggle them.
I had to replace my terminals for a similar symptoms.
I had to replace my terminals for a similar symptoms.
MBWorld Fanatic!
Joined: May 2022
Posts: 1,917
Likes: 499
From: The Netherlands
2005 CLS55 AMG W219 C219
Battery drain is almost never straight forward with our cars. I drive a W219 CLS, but the copy paste below will be applicable to W211 chassis as well.
Then you definitely have some draw. I posted this a couple times, as I was also searching for a drain:
I also had a power drain issue on my CLS55, to be honest I am not sure what I exactly did to solve it, but its highly strange that you cannot access the AGW with your Autel. I also have an Autel and was able to access it and code it where necessary. Some things:
-I also changed my alarm siren/horn. It wasn't working properly anymore and is a known culprit for power drain
-The CD changer needs to be connected with the power cables, else the headunit wont turn on. You can test this easily by drawing the fuse for the CD changer
-If you disconnect MOST components, you also need to adjust the coding for it. Else the AGW will expect the component to be there
-I also removed my phone + cradle in the arm rest. It always felt warm, meaning it was using power.
-I also replaced the BCM with the newest revision (I bought a 2nd hand from a 2007 E-class)
-I also replaced the AUX battery relay under the scuttle. If the AUX battery isnt charged properly, then it will keep asking for power from main battery if I am not mistaken
-I disabled the Interior Motion Sensor for the time being
-I serviced all (or almost all) earth points in the car, removing any corrosion and scuffing them up
[edit]
And:
I was also searching for parasitic drain. Some things:
- Search on Youtube, there are quite some videos on this topic, especially for W211
- Seat control modules are a common culprit, you can test this by pulling out the fuses and checking the draw
- Alarm siren is a common issue, with age the onboard batteries will fail to hold charge. The alarm siren will keep requesting current from the car, preventing it from sleep and draining the battery
- Audio Gateway is a common issue
- Navigation unit can cause drain
- Voltage regulator can cause drain
- BCM can cause drain
- AUX battery can cause drain
- AUX battery relay can cause drain
- non-MB Original alternator can cause issues! There was a thread in W211 AMG section not too long ago if memory serves me right
I replaced my BCM (2005 CLS W219) with a BCM from a 2007 E-class W211. Also replaced the AUX relay, alarm siren, both batteries. I disconnected all Tele Aid/Phone capabilities and fiber looped out the components I dont need (you also need to code them out).
I can also highly recommend a bluetooth battery guard, it gives insight what is happening with the battery > https://mbworld.org/forums/c219/8443...ml#post8860681
I also had a power drain issue on my CLS55, to be honest I am not sure what I exactly did to solve it, but its highly strange that you cannot access the AGW with your Autel. I also have an Autel and was able to access it and code it where necessary. Some things:
-I also changed my alarm siren/horn. It wasn't working properly anymore and is a known culprit for power drain
-The CD changer needs to be connected with the power cables, else the headunit wont turn on. You can test this easily by drawing the fuse for the CD changer
-If you disconnect MOST components, you also need to adjust the coding for it. Else the AGW will expect the component to be there
-I also removed my phone + cradle in the arm rest. It always felt warm, meaning it was using power.
-I also replaced the BCM with the newest revision (I bought a 2nd hand from a 2007 E-class)
-I also replaced the AUX battery relay under the scuttle. If the AUX battery isnt charged properly, then it will keep asking for power from main battery if I am not mistaken
-I disabled the Interior Motion Sensor for the time being
-I serviced all (or almost all) earth points in the car, removing any corrosion and scuffing them up
[edit]
And:
I was also searching for parasitic drain. Some things:
- Search on Youtube, there are quite some videos on this topic, especially for W211
- Seat control modules are a common culprit, you can test this by pulling out the fuses and checking the draw
- Alarm siren is a common issue, with age the onboard batteries will fail to hold charge. The alarm siren will keep requesting current from the car, preventing it from sleep and draining the battery
- Audio Gateway is a common issue
- Navigation unit can cause drain
- Voltage regulator can cause drain
- BCM can cause drain
- AUX battery can cause drain
- AUX battery relay can cause drain
- non-MB Original alternator can cause issues! There was a thread in W211 AMG section not too long ago if memory serves me right
I replaced my BCM (2005 CLS W219) with a BCM from a 2007 E-class W211. Also replaced the AUX relay, alarm siren, both batteries. I disconnected all Tele Aid/Phone capabilities and fiber looped out the components I dont need (you also need to code them out).
I can also highly recommend a bluetooth battery guard, it gives insight what is happening with the battery > https://mbworld.org/forums/c219/8443...ml#post8860681
Out Of Control!!
Joined: Apr 2019
Posts: 12,000
Likes: 6,827
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
sleeping with one eye... polling-status
Many things are helping drain your battery while parked. In my experience mostly the countless CAN-B modules.
> SCOPE...
Here I will address standard drains from factory that kills battery in a week or more.
There are also extreme drains when water penetration got involved. Usually F-SAM gets a shower then the unprotected circuit board dies from serious oxidation... search for signs of water under footwell/trunk carpeting.
> WORKAROUNDS....
Until you can get this nearly under control use a battery "float charger" at home and "jump pack" on the go.
> Death By Thousand Cuts...
The car has multiple low power stages used to sleep and partially wake-up.
This is managed by the Front SAM that is partially powered up 24x7 to poll security status and wake up necessary modules.
CAN-B modules are all those connected to chassis:
These modules are designed with marginal connections that mature into poor connection ready to become no connection.
F-SAM has multiple relays to segment modules into separate strings for which it controls power.
When F-SAM checks polls for status and specific modules don't reply system gets hanged for minutes instead of seconds.
You can easily notice this when reaction delays are involved.
Ex: you unlock the car, open driver door then alarm honks as if it was still locked!
-- The good news is this is very incremental: each goofy CAN-B modules adds delay.
-- The bad news is any single CAN member can collapse the bus network into extra-slow unresponsive mode.
The best bet is to scan for wonky modules always causing faults, fix them then repeat for next until 100% coverage. Then you'll have unusually fast CAN without "drain while parked" good for over 3 wks.
> SCOPE...
Here I will address standard drains from factory that kills battery in a week or more.
There are also extreme drains when water penetration got involved. Usually F-SAM gets a shower then the unprotected circuit board dies from serious oxidation... search for signs of water under footwell/trunk carpeting.
> WORKAROUNDS....
Until you can get this nearly under control use a battery "float charger" at home and "jump pack" on the go.
> Death By Thousand Cuts...
The car has multiple low power stages used to sleep and partially wake-up.
This is managed by the Front SAM that is partially powered up 24x7 to poll security status and wake up necessary modules.
CAN-B modules are all those connected to chassis:
- 4x Doors/Windows modules
- Headunit,
- IC Display,
- Air-conditioning module
- Front Seat controllers
- Sunroof,
- Trunk lid,
- F/R-SAM's,
- CGW itself,
- ...., ....., ....
These modules are designed with marginal connections that mature into poor connection ready to become no connection.
F-SAM has multiple relays to segment modules into separate strings for which it controls power.
When F-SAM checks polls for status and specific modules don't reply system gets hanged for minutes instead of seconds.
You can easily notice this when reaction delays are involved.
Ex: you unlock the car, open driver door then alarm honks as if it was still locked!
-- The good news is this is very incremental: each goofy CAN-B modules adds delay.
-- The bad news is any single CAN member can collapse the bus network into extra-slow unresponsive mode.
The best bet is to scan for wonky modules always causing faults, fix them then repeat for next until 100% coverage. Then you'll have unusually fast CAN without "drain while parked" good for over 3 wks.
Last edited by CaliBenzDriver; Aug 17, 2024 at 03:47 PM.
Junior Member
Joined: Dec 2020
Posts: 46
Likes: 3
E320
I recently purchased a 2005 W211 E320. After driving for a day, I am getting a ‘low battery convenience functions unavailable’ error.
I have checked the battery in the trunk, the small battery, and the alternator. Both AutoZone and the dealership confirmed that they are fine.
I replaced the auxiliary battery module as well, but I am still getting this error. However, it goes away after driving for a while. Does anybody have any suggestions?
I have checked the battery in the trunk, the small battery, and the alternator. Both AutoZone and the dealership confirmed that they are fine.
I replaced the auxiliary battery module as well, but I am still getting this error. However, it goes away after driving for a while. Does anybody have any suggestions?
if I were you though try removing both fuses for seat control module. 30 amp Left of stearing wheel with door open. Behind panel. I hear these seat modules tend to have parasitic drains.
Junior Member
Joined: Dec 2020
Posts: 46
Likes: 3
E320
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Out Of Control!!
Joined: Apr 2019
Posts: 12,000
Likes: 6,827
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
800Amps cable....
The main GND strap is located where tranny meets engine. It connects 100% of power consummed by the chassis its attached to.
You can deoxidize it and best thing is to double it with one or more backup cable located higher up where it's dry.
The goal is to connect chassis metal to engine.
If you can use a DVM measure between chassis and engine to see voltage drop.
You can deoxidize it and best thing is to double it with one or more backup cable located higher up where it's dry.
The goal is to connect chassis metal to engine.
If you can use a DVM measure between chassis and engine to see voltage drop.
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Junior Member
Joined: Dec 2020
Posts: 46
Likes: 3
E320
The main GND strap is located where tranny meets engine. It connects 100% of power consummed by the chassis its attached to.
You can deoxidize it and best thing is to double it with one or more backup cable located higher up where it's dry.
The goal is to connect chassis metal to engine.
If you can use a DVM measure between chassis and engine to see voltage drop.
You can deoxidize it and best thing is to double it with one or more backup cable located higher up where it's dry.
The goal is to connect chassis metal to engine.
If you can use a DVM measure between chassis and engine to see voltage drop.
MBWorld Fanatic!
Joined: May 2022
Posts: 1,917
Likes: 499
From: The Netherlands
2005 CLS55 AMG W219 C219
I made another one from subwoofer cable and placed it in the same position as a sort of redundancy. I read somewhere here that the W204 strap is an upgrade, as its shielded > A2045407135
Junior Member
Joined: Dec 2020
Posts: 46
Likes: 3
E320
