goober71

Hi All,
I have a 2014 E 350 sport with around 36K miles. Still under the extended MB CPO warranty.
About 3 months ago, I started getting the "auxiliary battery malfunction" message every now and then. i checked with the dealer and they recommended a battery replacement for around $250. I said no thanks.
I found information on here about the replacement auxiliary battery from Autozone. I replaced it last weekend. The switch out was pretty painless, and the battery works fine, but the ECO indicator in the dash will still not turn green. I've been driving pretty long distances over the last few days, but no luck. Weather is in the 50s-60, so that should not be an issue either. The ECO button has the green light on and the HOLD function works fine. Tried toggling the ECO button on and off, but no luck.
Any ideas? Anyone experienced the same issue? Do I need to take it to the dealer?

Thanks.

G

kajtek1

What ECO indicator you are talking about?
On my 2014 model, I have green block with ECO in it coming on when computer shuts down the engine for short stop.
Noticed that older models have ECO letters showing in yellow/green when system is ready ( I assume) but later models. don't have it.
I had autotell scanner who had ECO function troubleshooting. The display had 12 sensors that needed to become active for function to kick-in. That incluse airmatic, who was excluded on my car.
So final conclusion, when weak battery is most often reason for ECO not engaging, there is much more and without scanner, the glass ball is not very efficient.
Get a scanner !

QUICKSHIFT

Just came from the dealer today for the exact same reason. A new MAIN battery fixed the problem. Now I have to remember to turn the ECO switch off every time I start the car again!

KEY08

ygmn

Dealer should have changed Aux battery under warranty.

They did for me twice last year.

goober71

The dealer refused to change the AUX battery under CPO warranty. He said it was not covered, considered a wear and tear item!
I can bring it into Autozone and have them check the battery for charge. It does have the same specs as the MB battery, 12V, 200CCA. Supposed to be a drop in replacement.
And the ECO feature i have is the word "ECO" displayed in yellow in the dash, which turns green with a solid border around it when the system is ready to shut down the car upon stopping. Hope that helps.
Any other ideas?

Thanks.

G

KEY08

My Aux battery was replaced 10 months ago for free under CPO, so I think your dealer is not such a nice shop. Maybe call MB and ask. In any event, you need to get it back to the dealer for diagnostic to determine the problem, if not battery related.I have yet to hear of a specific issue causing the ECO function to not engage. It is always the battery.

LALALAND

At least you have ECO showing yellow/green in the multifunction display. My car don't have the it in yellow when it's not ready yet. Haven't saw ECO in green for like 6 months. When I originally bought the car I swear that I have ECO in yellow on screen, but somehow it disappeared. Even with a 50 miles drive on freeway, the ECO stop didn't even activate once after I get into the streets. Now it was cold yesterday and I had passengers in the car that complain stuffiness.I had temperature set at 70 with AC off and turn up the fan speed instead of Auto (fan speed was too low in Auto for 5 ppl). Still haven't see the aux battery malfunction message yet so I didn't replace the aux battery. Just think of it as Mid-city mod for to remove ECO for free.

Anyway, I did found out that the climate control is part of the parameter for ECO activation. Put it in in Auto with AC on, and the ECO might show up faster.

goober71

So, i have an update on this. I brought the car to the dealer to show them the issue. They ran diagnostics on it, and told me that the main battery (starter battery) failed their "Midtronics test". That is why the start/stop feature is not being activated, even after replacing the AUX battery. They recommended replacement of the main battery for $400+.
Since the car starts and runs fine for now, I declined the replacement. I'll go to Autozone and buy a new battery for $199 + tax when i start seeing issues starting the car in the morning.
I've been very UNIMPRESSED by the local dealer here (MB of Sugar Land). I expected a higher level of customer service from MB dealers, but turns out they're just trying to make quick bucks off their customers.

G

kajtek1

PepBoys have sale on their batteries and when Bosch is always good value with them, member just bought Champion AGM for about $140. Check parallel topic.
Also if you are big fan of MB batteries and have been using dealer service in last 2 years, you can call their roadside assistance and have the battery replaced on your driveway with no labor cost.

Mud

I'm up in Conroe and luckily MB Woodlands has been excellent. Too far for you though, I know.
I'm the member Kajtek mentioned. Thx to another member cetalpha5 I just bought Champion H8 AGM from Pep boys. 4 yr warranty.

Until Jan 27, buy online and get 25% off, plus $40 mail in rebate. Pick up in local store then return old battery for $18 core. Great deal overall.

Battery

pezzy669

Same here - when I moved from Volkswagen and Mazda to Mercedes I wrongly assumed I would have a better service experience. Entirely wrong - my Mazda and Volkswagen service experiences blow my MB service experiences out of the water. I am walking distance from the "premier" MB dealer in Atlanta (MB of Buckhead) but am now opting to drive 18 miles to an independent for service since I am well out of warranty and don't really need to go to the dealer. I'll still pop in there for parts here and there but other than that its now a hard pass for me on going to them for service.

kajtek1

You can get some impression how stealers value customers by asking about new key pricing.
When I was living in California, I had 8 dealers within 1 hr of driving.
Few years ago key quotes ranged from $180 to $ 440 and anything between. Guess where did I go?

MBENZTECH

Batteries are not covered under the CPO warranty. To the OP (GOOBER71), shoot me a PM when you get a chance.

Mlv

I have MB 2014 e350. ECO light turns off by itself while driving. When the light goes off, the car starts to shake. Any ideas on why this would happen? Almost feels like it's going to stall.