E300 Hybrid System not engaging

[Serega]

Even

Now in the winter time? When outside temp is below 0 ^ Celsius? Your hybrid system still works?

Yes, it works at any temperatures.
The Ready indicator becomes green after couple of minutes even at -10.

 

[Fedaykyn]

Strange... now in the winter time mine is Ready green all the time but always moves from place (goes on the road on diesel power)... it starts on hybrid mode no Diesel engine... but when it’s put on D / R (drive or reverse) when starts moving the Diesel engine comes on automatically.... the MB Service said it’s ok - no errors on hybrid systems...

 

[Serega]

Strange... now in the winter time mine is Ready green all the time but always moves from place (goes on the road on diesel power)... it starts on hybrid mode no Diesel engine... but when it’s put on D / R (drive or reverse) when starts moving the Diesel engine comes on automatically.... the MB Service said it’s ok - no errors on hybrid systems...

Sometimes, absolutely the same appeared with mine.
Now I do not have such problem.

 

[James Ireland]

Hi there. I know its a while since this thread was discussed. But I am having the same issue. The green ready indicator does not come on as much as it used to, even in summer months. My car has had quite a lot of short city drives. Recently, I had to do a motorway three hour drive and after that, the green ready indicator was coming on as it should. This lasted maybe two months. So I am wondering if there is a DPF regen issue or something similar which is causing the amber light to appear more often than normal. An help appreciated. Other than this, the car is going fine. But I'd like to get it back to normal.

 

[Serega]

Hi there. I know its a while since this thread was discussed. But I am having the same issue. The green ready indicator does not come on as much as it used to, even in summer months. My car has had quite a lot of short city drives. Recently, I had to do a motorway three hour drive and after that, the green ready indicator was coming on as it should. This lasted maybe two months. So I am wondering if there is a DPF regen issue or something similar which is causing the amber light to appear more often than normal. An help appreciated. Other than this, the car is going fine. But I'd like to get it back to normal.

Hi,
I would like to recommend you to charge your battery, then check how the hybrid system will work.
If it will, so the main battery is dead.

 

[James Ireland]

Hi,
I would like to recommend you to charge your battery, then check how the hybrid system will work.
If it will, so the main battery is dead.

Thanks for the advice. I will try it.

 

[James Ireland]

Thanks a lot Serega. We replaced the normal battery at a cost of 100 euro and bingo, car is running superbly. This is something all owners should be aware of as I am sure that some have had to fork out thousands for new hybrid batteries when they weren't even necessary.

 

[Raymund]

Same problem, changed battery and working perfect now. Thank you Serega.

 

[Bijan]

MB E-300 Blue Tec Hybrid. After reading your comments, yesterday I changed the AGM battery and it immediately engaged and is working perfectly. With many thanks for your advice.

For the past 6 months, the diesel engine would not disengage and the "Ready" sign remained amber. My repair shop computers couldn't pinot the problem. At first they thought it was the main Hybrid battery that had degraded. Later they though there was a fault in the computer system.

On a related subject, could someone tell me what components of the vehicle the AGM battery provides electricity to and the same for the stop/start battery? While the AGM battery was degraded, the vehicle would start.

With thanks,

Bijan,

Cobham, Surrey

 

[Marcus M]

Hi, I’ve had my e300 Hybrid for about 3 months now. Superb car after spending a little on maintenance, car has had one owner and 118k miles on the clock and plenty of Mercedes service stamps. However I have noticed that it seemingly never operates on battery alone, as soon as I turn the car on even when the ready light is green and the batter is at 80-90% the diesel kicks in automatically 100% of the time. It’s returning about 25mpg city driving and 50-60mpg on the motorway. I suspect the hybrid element has not been engaging as it should be fit to reverse in a car park etc purely on electric? Has replacing the normal battery solved the above for any of you?

thanks

 

[Nigel Hewitt]

It does that in the winter so it can run the car heater/demist/et al.
It doesn't revert to full stop/start until it's sure you're warm.
Perhaps yours is forgetting to drop out of that mode.

 

[dsharples]

I've had my E300 Hybrid for 5 years now, and until recently, its never failed to start under electric power with a "green ready" even in (UK) winter - and often required me to start it with the door open if I wanted quicker heat .

It was often a chilly 5/6 mile regular drive to work.... but no problem once you knew this. I was more worried about the mechanical impact on the engine parts stopping and starting when very cold... This also wasn't on problem for my occasional but regular longer journeys of 250-500+miles in a day!

"Recently" was caused by my local MB dealer allowing the "battery to go flat" during a navigation update whilst the car was in for other work to replace a waterlogged rear SAM which was causing the brake lights to remain on :-o.

Having complained when the car was subsequently due for a service - despite no recorded faults, at my insistence of checking they found the AGM battery to be not holding its charge properly, and changed it with a good discount I was happy with... so all good you may think.. but no...

The car still does not start on electric power unless the engine has been run for 5 minutes or so, and will not stop the engine/use hybrid mode in that time. And strangely that time reduced the day after the car had a 200+ mile run - i.e. a after couple of minutes running (if that) enabled the car to work normally.

This still suggests to me a low voltage condition..... So I was wondering if its actually the (little) Auxiliary Battery which is also in the boot.

Of course, it could also be different firmware / software versions / integrations with the main systems of the rear SAM....

But... the Auxiliary Battery does seem to be showing some signs of corrosion on its +ve terminal, so I was considering changing that too, as I happen to have a spare (new, genuine MB) commercially sourced one.

But my question is whether there are any special precautions I should take in changing it. I'm aware the battery systems on the E300 are complex!

Providing I shield the positive terminal, can I just pop the boot, pop the floor, pop the liner, undo the bracket, and swop them over... as I would any other car battery - or should I/do I need to disconnect the main AGM battery in the boot first, and then are there any weird things like windows to reset etc.

Thoughts/guidance welcome.

 

[Marcus M]

I am also interested in this post as the weather in Glasgow is now around 10/12 degrees and the battery should operate the car on its own and it never has over the time I’ve owned it. I’m going to replace the AGM battery first to see does that solve it @dsharples do you know can you just swap out the battery without causing any electrical fault or does it need to be done by a mechanic?

Let me know how relaxing the auxiliary goes as I have seen that on YouTube solving some issues.

Also does your e300 have a start/stop button as mine doesn’t

 

[dsharples]

I am also interested in this post as the weather in Glasgow is now around 10/12 degrees and the battery should operate the car on its own and it never has over the time I’ve owned it. I’m going to replace the AGM battery first to see does that solve it @dsharples do you know can you just swap out the battery without causing any electrical fault or does it need to be done by a mechanic?

Let me know how relaxing the auxiliary goes as I have seen that on YouTube solving some issues.

Also does your e300 have a start/stop button as mine doesn’t

No, there is no start/stop optionality. Every time you lift off the accelerator, the engine should shut down! Once the car is up to temperature this should definitely happen. In start-stop traffic / queues mechanical sympathy encourages you to try and move around on electric power - as the engine otherwise fires up and shuts down continually if you are too heavy on the throttle. I can't remember the parameters for the hybrid system to engage, but battery volts I'm sure is one. I would suspect that the car has to know the AGM battery has sufficient power to restart the engine, and the auxiliary battery has enough power to hold the transitory load between the different power systems. I was told that is what's its there for - to hold the cars systems power momentarily between the 48v hybrid battery systems and 12v systems being switched around and utilised by the car.

As you can also read, each one of us seems to have a slightly different experience of their E300 Hybrid. I don't know whether its usage patterns, or software/systems upgrades during manufacturing or after-sales/service. Mine was an almost-unused ex. MB UK Fleet / Showroom Demonstrator, and seems to have been "relatively well sorted" before I purchased it. Others have not been so lucky. Its had it moments though, and has not been trouble-free....

Mercedes owners don't seem to be into the details/diagnostics of their cars like other modern cars/marques I've owned - so there doesn't seem to be much info on the internet. The common answer seems to be "consult your dealer or friendly specialist"......

 

[RDS]

I have had my E300 since June 2019 and I realised after a few weeks that it didn't run on the Hybrid system as much as I thought it should do. I had the Main Battery replaced at the Mercedes Dealer and it has been as different again ever since. The engine switches off as soon as I take my foot off, after no more than a few minutes running, presumably when it has warmed up slightly. If I have used the car within the last few hours, it sets off on Electric straight away. Hope this helps.

 

[jp williams]

I have had my E300 since June 2019 and I realised after a few weeks that it didn't run on the Hybrid system as much as I thought it should do. I had the Main Battery replaced at the Mercedes Dealer and it has been as different again ever since. The engine switches off as soon as I take my foot off, after no more than a few minutes running, presumably when it has warmed up slightly. If I have used the car within the last few hours, it sets off on Electric straight away. Hope this helps.

Was it replaced free of charge as it should have been ?

 

[RDS]

No, I should have said, it's a 64 plate model.

 

[Serega]

Now my Hybrid battery is finally died...

A diagnostic had appears a lot of different fails.

Main problem is the difference in voltage between battery cells (one of 35 has a voltage ~2,5V, the others 3,55V +/- 0,02V), also the contactor reached the number of connections, so the battery is disengaged.

The main symptoms are:
- there is a push during drive and then the car does not go for a couple of seconds;
- battery doesn't charge at all;
- the car jerks when braking and accelerating;
- a/c doesn't works.

Now the car is at service, the master promised to repair the battery.

 

[RDS]

That is of course disappointing but it will be interesting to see if the battery can be repaired, presumably by replacement of just the faulty cells.
Best of Luck, I hope it goes well for you but please let us know what happens.

 

[Serega]

Yes, it can be repaired. He has already repaired several batteries, so my battery is not an experimental for him
The main problem is that the battery is non-disassemblable ant it takes a time to disassemble it.

Thanks, I let you know about results soon.