jhorandc

03 MB E320 Sedan did not have enough power to start one morning. Key fob would not release trunk. After manually opening the trunk, AAA 'jumped' the rear main battery in the trunk. Car started. Dashboard displayed "malfunction electrical consumers switched off". Drove car to local shop. Rear main battery and Aux battery original. Local shop replaced rear main battery with high-end Interstate AMG battery. Car appeared OK.

Within a couple of days dashboard warning "malfunction electrical consumers switched off" returned. Took car to the local shop. Aux battery was replaced. Car appeared OK.

Within a couple of days, dashboard warning "malfunction electrical consumers switched off" returned. Waited 1 day to take it back to the local shop. That day the battery(s) had no power. Even the key would not turn. Called AAA for a jump start. Car started. Took car to the local shop. By the time car arrived at the local shop, warning was gone. Local shop used a Mercedes scanner. No faults found. Brought car home.

Made appt with Mercedes dealer for the next day. Expected the car to have a drained battery in the morning. Car and battery were fine. No warning. Went to Mercedes dealer service. Was told to return when warning or issue returned.

Have read various possible causes from battery control module, to voltage regulator, to alternator, to not resetting the car's computer to '"tell" it there is a new battery. Concerned the issue will return.

Any ideas?

cetialpha5

Keep an eye on the voltage. Switch to temperature display and hit the reset button 3 times while the car is on, but not running. Should display the voltage. Then see where it is when you start it and when you shut it off. The low warning kicks in when it's below 11 volts. For a 2003, my guess would be the battery control module.

And it's an AGM battery, not AMG...

jhorandc

Thanks. My 2003 might not have the voltage menu. Have tried without success. Read a note on another page that this option is available for W211
2004 – 2009 E C CLASS.

If the battery control module is the culprit, would a Mercedes scanner (e.g. DAS Xentry) identify it as faulty or is there another test?

ot1

kajtek1

Would you have problem with charging, the red message would appear, but if you have over 100k on the car, replacing VR is not bad idea.
You might have couple issues when bad battery was start. The car is very sensitive to all connections, so clean battery clamps and make sure they are torqued properly. It happen to me that I had the convenience message for 1 week on my vacations only to find not torqed clamp on my return home.
Than observe if your car goes to sleep within 10 seconds. Do you use Bluetooth for phone? When you park car at home, do you take the phone far away from the car to disconnect Bluetooth?

jhorandc

Thanks. In response to the Bluetooth question, the car is parked at night a good distance away from the house.. Is Bluetooth auto-enabled on the car?

Would a MB scanner pick up a faulty VR?

BTW, I am on day 2 with no issues. Car starts fine in the morning and no malfunctions.

kajtek1

There is no code for wear out alternator brushes, You will see low voltage and associated warning when they start going bad, but they can act for long time before they die.
Per my experience Bluetooth connection dies when you go about 40' from the car and you have garage wall between, but when you have trouble, not bad idea have somebody carrying your phone away and observe when the lights die.
On my 2008 the puck has blue light on it, so easy to observe.
The Bluetooth issue come to the attention when some members report that being inside the house, the phone calls were answered by the car.
That was when I timed that car goes to total sleep in about 10 seconds, unless something keeps it awake.
Bluetooth alone will not drain battery overnight, but some other things going on can add to the problem.

jhorandc

Car was fine for 3 days before December 25. It was driven daily. It wasn't driven on December 25. On December 26, the car was completely without power. Even the key fobs would not work. The main rear battery measured 4.7 V. AAA called to jump the car. Car then taken to Mercedes service for diagnosis of the issue. Not sure why, but Mercedes service asked for the 2nd key as part of a diagnosis. Anything special I should ask Mercedes service to check?

jhorandc

Mercedes Services believes it is the ignition switch that is causing the battery drain. Dealer charge to replace is about $1600. Comments please?

cetialpha5

That's interesting. Usually EIS is a different problem, not sure if those vendors on eBay can fix that, but it's $200-$250 to have it repaired. But you have to remove it yourself. If you get it done quick, you can use the $150 off $300+ service coupon.

https://www.mbusa.com/mercedes/servi...n_back_savings

https://www.ebay.com/itm/MERCEDES-BE...E/173118682175

https://www.ebay.com/itm/Mercedes-be...E/113446876238

jhorandc

I need to confirm that the EIS issue found by the dealer is definitely related to a battery drain issue. MB Service ensures there is a 99.9% chance that the problem is the ignition switch.

jhorandc

Mercedes Dealer Service had two '03 E320's in the shop. They were reporting the issues with the other E320 that was towed into the dealer. It was the one with the bad ESI. Even my invoice had a description of the 'other' E320. After contacting the dealer and a different service adviser, describing to them that I drove my E320 into the shop for a battery drain issue were they able to find my E320. In less than 2 hours, they found that the power seat modules were the source of the problem by measuring voltages. The tech suspects a short in the modules (right and left). The tech knew these modules were often a problem with the E320 battery drain issue.