Electrical Consumers Switched Off
I got the electrical consumers switched off malfunction today. Both batteries are less than 1 year old and the alternator was also replaced at the same time (last September). Drove the car 2 days ago and everything was fine.
Checked the voltages as follows:
Not running:
Main battery 12. 8v
Aux Battery 12.7v
Running idle:
Main battery 13.5v
Aux Battery 12.7v
Took the car for a quick run - about 5km (about 10 - 15 minutes). When I came back and checked the malfunction message was gone. Checked the voltages again and got the following:
Not running:
Main battery 12. 9v
Aux Battery 12.8v
Running idle:
Main battery 13.9 - 14v
Aux Battery 12.8v
Noticed that the running voltage was higher than before. Am going to check again tomorrow morning when the car has been sitting a day and half to see if it is a parasitic draw.
Any other suggestions to check?
Thanks in advance
Roshan







- Alternator itself
- Battery Control Module (BCM)
- Earth straps/earth points
Could also be parasitic draw, but my first suspect would be the regulator and/or BCM. If you want to monitor the battery, add a battery guard. I can highly recommend this, so you can see what is happening with the battery voltage.



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
Last edited by nd-photo.nl; May 1, 2024 at 09:51 AM.
Update to the parasitic draw. Turned out it was the Parktronic control unit. With everything powered off there was a draw of 2.8 amps. Fitted a used unit (unfortunately new not available), the draw reduced to 0.061 amps.
Thank you everyone for the assistance.
Roshan


