007_e350

I was getting Low Battery - Convenience Features Disabled message while city running alongwith ABS & ESV malfunction messages (total 3 messages in all). There are no problems starting the car.

So, I just changed both my batteries but I got this message again today... I went into the special menu & read UB: 12.2 volts right after the message came on (alonwith ABS & ESV malfunction messages). During the drive it shows 14.1 volts mostly. (The car had headlights on, fan at 3 and audio on) ...

Why is the ABS & ESV lights coming on with Low Bat ? I recently bled my brakes too, is it possible the ABS sensors went bad ? But why are they associated with Low Bat ? My steering also gets hard after these messages. Also, if I restart the car all 3 messages go away ... not for long though

I called the stealership, they say they need to run diagnostics to check current leakages draining the battery... $195 dollars for diagnostics only.. pls help

Diesel Benz

So the battery voltage was still at 12.2 before you started the car? Doesn't sound bad to me if the car had been parked overnight or so before that.

How did you perform the SBC brake system bleed? Do you mean ABS/ESP malfunction? And it only appears as long as the battery voltage is low? 12.2 should be enough for ABS, sounds odd.

You can diagnose current leaks yourself but you should be sure that there is a current leak issue first. I would use a multimeter to measure both batteries after the car has been parked.

007_e350

Diesel Benz, the low-batt came during driving (it always did in stop & go traffic), I was at a red light & quickly turned the car off and punched the sequence, got into the special menu to read voltage -- Vettdvr told me Low batt would come below 12.5 v --- what I dont understand why it dipped down from 13.4 to 14.1 v (alternator charging) ..
Regarding brake bleeding, I just did it the conventional way - and I think I've hurt the SBC pump (as it doesn't buzz when I unlock the car eversince, I can hear 2 clicks like it tried but could'nt buzz..), No errors on FSS and brake is normal though

Current Leak Test:
I read this document, bottom line is to disconnect BCU's -ve line and insert voltmeter between BCU and battery - then check for current leaks:
1- if the leak is from 1.5 to 2.5 Amps, the bus hasn;t slept yet - so something needs to be changed
2- If the leak is 60 to 120 mA, check individual switches (I saw 4 near the batt) by taking one out at a time to see if leak goes away (elimination process - the algebric term) - replace the fuse

Is this the right process, can anyone verify before I ruin my electrical system ..

007_e350

Here's the document.. anyone's done this before ? any tips ?

vettdvr

It is possible to have lost reserve capacity in the battery or have an internal short that could result in either low surge or high current to keep the battery charged.

I still suspect a main battery is the suspect.

I changed mine at 87,000 miles with date in service from 8/02 - 9/09 which I thought was good / excellent battery lift. I bought a replacement from Carquest. The foreign battery they sold was identical to the OEM down to the correct vent connections. From my detective searching (if I remember correctly) The carquest and OEM were made in the same factory.

007_e350

I judt plugged in the voltmeter between battery's -ve lead and the BCU ... There's a surge of 3.29 Amps even after the car's completely shutoff ... I tried plugging out fuses, it reduces to 1.8 Amps after one switch taken out --- I have no clue now ... taking it in tomorrow to get ripped off

007_e350

Hey vettdvr, I just put in a brand new battery (actually both of them) --- Now I get a Red Battery sign ... it does read out 12.6 volts, not to mention despite the 3 Amps leak..
My last activity prior to low batt / ESP / ABS warnings was brake fluid bleeding - I wonder if the SBC pumphas gone nuts, I didnt disconnect it during bleeding.. what do you think ?

vettdvr

Start the engine and measure the battery voltage. What is it? This will tell you if the charging system works. If the system works it is still possible to have 1 of 3 diodes in the alternator bad but it will at least give you more information. If you are getting 13.2 - 13.8 you alternator will be charging. If it charges and the batteries are new I would think the battery warning wouild go out.


However did you drive it? Do the brakes work properly and verify the brakes work without a brake warning. If you have no warning it is probably ok.

007_e350

just got a call from the SA, both main batteries are not providing enough amperage (old mercedes one & the New one I put in) ... He says everything else checked out fine
he says $600 for the new battery ... I'm getting 1050 CCA Excide OEM battery from NTB today & going to return this crappy advance auto parts one...

He told me my front lower control arm bushings are showing signs of crack ... $1050 for the job.. Man this car will always have a project for me!

vettdvr

Glad you got it worked out.

Apparently, it actually was a low reserve battery capacity.

This is why I bought from carquest the AGM identical replacement battery. Cost me $225 total but it was made apparently by the same company that makes the MB OEM battery and identical physical and electrical capacity.