ECO stop/start intermittently working : C220d 1/2018

[SG94]

It was the AC primarily, but there were a combination of things including sensors, software and a cable. This then got it working to some extent, and they once took my car for 2 weeks for extensive testing. The service manager then proudly announced it was fixed as he had had it running for 2 weeks perfectly.
What we stumbled upon completely by accident was the AC issue. I collected the car and all was well for a few days, I then noticed that all the climate control etc was off. As soon as I turned it back on, the SS immediately disabled and stayed off. I tested this for a couple of days, AC off - perfect SS, AC on - no SS at all, it never even activated.
Phoned the dealer and spoke to the manger who asked me to bring it in, we went for a short drive and I showed him. Apparently he never uses AC or climate control in his car (I’ve had ‘his’ car as a loaner a few times and it is always off). Anyway, they took it back, changed a ‘board’, and it’s worked since.

Try it. Turn everything off, everything, and see if you can get it to work. Then start turning stuff on one by one and see if anything turns it off.

 

[zena123]

Thanx SG94 and Markjay. Was at funeral yesterday, so no chance to pick up posts till late at night. At Garage today, they diagnosed a Battery Sensor fault. Does that Sound feasible? New sensor is coming at 3pm and will be fitted. Collect car around 5pm. Then i will try SG94s suggestions to turn everything off & try variables out one by one over next few days. Will update, if things go well or badly. Meantime, your ideas ( as relayed by me) went down reasonably well with the Garage, i.e. if battery were faulty, they would replace it. So: many, many thanks ! Service Plan i hope to defer to Black Friday (29 Nov); either way it makes sense until I find an Indie after warranty has run out, I'm thinking ...

 

[zena123]

P.S.Garage say they carried out a Health Check as well on car today ..will see results online when back home. Bw Helene

 

[markjay]

Thanx SG94 and Markjay. Was at funeral yesterday, so no chance to pick up posts till late at night. At Garage today, they diagnosed a Battery Sensor fault. Does that Sound feasible?...

Yes it does

But if that does not fix it... then you will need a new battery (one or two).

 

[zena123]

Good morning all! Am I fussing unnecessarily ??? …. Drove from garage yesterday about 6pm : S/S working fine. They'd replaced the battery sensor & did a ‘Health Check’ on the car. On advice of garage, I used no aircon, but had forward-facing camera running off 12V cigarette connection + radio/Navi on. (Journey 1): Traffic on M25/M1 varied, some stop-start, but no lengthy queuing. Was mostly 40-60mph to Junction 9 (M1), where I left to call on family & (Journey 2): local friends. (Journey 3): at 11pm - with less traffic & could boost battery by driving consistently at 50-60 mph on M1 (inside lane!) with a brief increase to 70mph. Lights, obviously, were on + Navi/radio, but no camera connected. A couple of times on North Circ. at traffic lights, the car seemed slow to get into gear: other cars drove off & I had cars behind me, waiting. Afterwards I noticed that S/S indicator was off for remaining journey. What I am getting to here, is: delay at traffic lights could have been my driving at fault (maybe I didn't put foot hard enough on accelerator pedal) but car seemed to 'hover' for a while before engaging gear. Is this to be expected ? [I am, of course, comparing it to my ex- Golf, where, when you pressed the pedal/engaged gear, there was no doubt about forward propulsion.] Am just wondering about getting an AA check done on the car, for peace of mind. I'm sure the garage has done all the necessary compliance checks re: HPI, ownership etc. so it’s mainly a question of being sure the mechanics work properly. [Fri a.m.: Have just been ‘round the block’ in the car & S/S is working fine.] I'm off out shortly (slightly longer trip) & will see how it goes before initiating anything with the AA, & hope I'm just fussing about nothing. What would you do ? (bought car on 31aug2019) tx as always - gratefully, Helene

 

[ToeKnee]

The stop start on my car works faultlessly 95% of the time but occasionally, for no apparent reason, it won't work at all. This happens totally at random, no matter what is switched on or off, I've just put it down to a work of the car and live with it.

 

[Eddy77]

We have a S/S on our A6 and it does this. Doesn’t always kick in as you’d expect. One thing Audi’s do is disable S/S if the gearbox is in Sport mode. Don’t know if Mercedes do anything similar????

Mir doesn’t bother me much to be honest, but I can confirm that from day one it has not always activated S/S at standstill. I put it down to all the variables previously mentioned like engine temp, heater settings etc.

 

[zena123]

Tx Toeknee & Eddy ... there's been a big improvement (so far !) after garage put a new battery sensor in. After reading all posts above, I realise it will never be entirely reliable, esp. if AC is on. But thanks to this site I know now it's not indicative of something really important going wrong (eg battery failure). Eddy: yes, there is a push button for disabling S/S : which I will use sometimes in future - as other posters said, it can be a nuisance. Thanks again to all who contributed, the issue is now sorted ! bw Helene

 

[Gavin14774]

Hi, I bought a 2013 C250 a couple of week ago and mine is behaving similarly. Can I ask though, do/did your Eco lights change colour? Most of the time the word Eco on my dash is in yellow then when the system decides to active it changes to a green rectangle with the word Eco in. I can’t see any pattern to it other than it rarely activates.

 

[zena123]

Hi Gavin14774, I'm still trying to work out the pattern .... a friend bought a 2014 C220 a couple of weeks after I bought mine & his ECO stop/start works perfectly well, in circumstances where mine wont work (which is pretty permanently now). I'm thinking of writing to Mercedes & asking whether it's reasonable to expect it to work, esp. as the car is not that old .... and given that the garage wasn't particularly interested when I raised the issue with them. They did however take it in (car still under warranty) and replaced a sensor (you may have seen in my previous post). In answer to your specific questions about Eco lights changing colour ... I'll take it out today & report back later, so that a more precise picture builds up. The only other thing that may be worth reporting on is a YouTube clip which I saw this morning: it says Eco won't activate when the car is set to Sport or Sport+ (i.e. only works on ECO or Comfort setting) - another thing for me to check out after lunch.

 

[zena123]

Hi Gavin, ECO stop/start did not function at all yesterday : indicator on dash was yellow with 'A' crossed out from start to finish. During journey, we stopped car & changed from 'Comfort' to 'Eco', to 'Sport', all of which should allow ECO stop/start. [Sport+ doesn't allow Stop/start]; indicator light in centre console (between driver/passenger seat) shone bright green, indicating that ECO Stop/Start should be available if other considerations listed in handbook are fulfilled, incl. no Air-Con. on [One of those is that the battery should be sufficiently charged ... which makes me wonder about the battery.] By comparison, friend's MB (2014) has ECO stop/start that functions consistently well. So I conclude that mine is NOT working as it should.

 

[Gavin14774]

Thanks, mine doesn't have an A so I'm not sure what that signifies. I think I'll start by getting the batteries tested.

 

[zena123]

How will you do that ? Pls let me know the results !

 

[Gavin14774]

Local motor spares shop has a meter they put across the terminals and it simulates a load on the battery and tells you what voltage it's putting out.

 

[zena123]

Update to original posts (September onwards), re ECO Stop/Start. Took car to different garage. Main battery working at 70% capacity diagnosed. Battery replaced under warranty. ECO stop/start working now. Will continue to monitor. Thought you might like to know. Still amazed by (& grateful for) all your helpfulness on this forum.

 

[markjay]

Stop/Start problems... 9 out of 10 it's the battery (main or auxiliary).

 

[jdrrco]

Start/stop makes so little difference to fuel economy etc, it's really not worth bothering about. The cost of new battery etc will not be recouped for a very long time.