W211 E55k Red battery warning.

[smoothcoupe]

Hi all,

Red battery warning appeared on my 2003 E55k over the past couple of weeks. Car drives perfectly fine, I put it on the iCarsoft MB II machine, and getting Fault 9092; component G1/7 axillary battery defective or not installed.

So as a matter of precaution, I went a bit overkill.. Replacing brand new Genuine aux battery, new Genuine main battery, new Genuine aux battery relay and new Genuine aux battery relay fuse...

The new batteries were manufactured few months back, and as I say, are genuine MB parts.

I Tried to clear the code on the machine after replacing parts, but still will not clear, and the battery light remains on.... Car producing healthy voltage, 13V static and 14.3V when running...... Can't understand why the aux battery relay is showing 0 volts on the MB II machine's status. Find some pictures attached.... any ideas??? Thanks in advance..

 

[91dm]

Someone said the wire going the fuse F30 was causing this fault? Where are you checking the readout, at the main battery or aux?

 

[smoothcoupe]

Someone said the wire going the fuse F30 was causing this fault? Where are you checking the readout, at the main battery or aux?

Reading on the datastream on the icarsoft MB2

 

[91dm]

If the OBD isn't seeing any voltage, a continuity test on the aux battery lead would be good to do?

 

[smoothcoupe]

If the OBD isn't seeing any voltage, a continuity test on the aux battery lead would be good to do?

Would I need to trace back to bcm in the boot any ideas which one to identify to test? Thanks.

 

[Alps]

aux batt is the one under the pollen filter airbox in the engine bay, not the big one.

 

[smoothcoupe]

aux batt is the one under the pollen filter airbox in the engine bay, not the big one.

Yes but was wanting to know where the positive cable from the aux battery ends up so I can trace it back. Is there any point in line fuse somewhere?? Also it’s now reading a voltage in the datastream on the icarsoft but only around 9 volts. The code does now clear but almost comes back straight away.

 

[pmcgsmurf]

Diagram attached.

 

[smoothcoupe]

Diagram attached.

Thank you much appreciated. Started car this morning, No warning on dash, no faults and aux battery now reading 12.8 on the I car soft… think the car is jinxed

 

[Supernoodle]

Diagram attached.

Thanks, that's a useful doc, not seen it before

 

[91dm]

That does sounds like a possible loose or bad connection? I'll take a look at mine and see what it says.