Stop / Start (ECO) not restarting engine

[dazblink]

Hi folks,

I must turn off my start stop on every trip because when it stops it kind of stalls when starting up again automatically then I get absolutely nothing trying to start the car again. The only way I have worked out how to restart the engine is by disconnecting the battery negative terminal and putting it back on and I can then start the car again. I have an icarsoft 2.0 diagnostic tool which I am getting 2 fault codes on but neither seem related to this.

I have recently had a new Varta F21 AGM battery fitted. I was having issues with the old battery and one morning when it wouldn't start my friend 'helped' jump start me. Only thing was the numpty put the terminals on the wrong way and blew a module in the front prefuse box. I got hold of a second hand prefuse box from a scrap yard fitted it myself and the car is back up and running again except for this issue with the stop/start.

Any suggestion please will be greatly appreciated?

 

[dazblink]

Is there a relay or a module that could have blown on the stop/start that is causing this?

 

[Tonygw]

I Dont know exactly, but apparently you can disable the stop start feature by removing the fuse in the rear fuse box in the boot right hand side, I think its a 7.5A. If that might be a cheap fix for you?

Other wise you ight need a proper Star diagnosis to resolve it.
Cheers

 

[dazblink]

I Dont know exactly, but apparently you can disable the stop start feature by removing the fuse in the rear fuse box in the boot right hand side, I think its a 7.5A. If that might be a cheap fix for you?

Other wise you ight need a proper Star diagnosis to resolve it.
Cheers

Nope I just looked down the list of fuses and I cant see a fuse for the stop/start (well not in the boot anyway). Thanks for your reply though

 

[MrGreedy]

Have you searched the forum on how to disable stop/start?

s/s is believed to be one of if not the number one contributor to snapped timing chains on the OM 651 engine (if that's the one you have?). Tend to be very hard on batteries, so they of course need replacing more frequently. More trouble than it's worth, and I bet over the lifetime of cars with these systems the total CO2 emissions saved vs. spent due to new components and everything associated with that is far less environmentally friendly than emissions figures would want you to believe from Euro certification tests when the engine is brand new.

Post in thread 'Which E class Diesel engine to go for.' Which E class Diesel engine to go for. | Engine

 

[Tonygw]

No its doesn't state its a fuse for stop start, its aux or something, I think Gazwould did it to his S204, its definitely possible. You just need to find the right fuse. He might be along to advise you on it.

 

[Gazwould]

Helloooooo..

Disable Stop Strain .

Two methods , remove Auxiliary battery 7.5A fuse .





Or remove the 5Kg battery altogether , I've done both methods with great satisfaction .

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[dazblink]

Cheers for the help guys. I did really want to diagnose and fix the issue but at least for now I will just take that fuse out. I've got tons of other issues with the car so at least I know I can take out the start/stop so its the least of my worries and I can concentrate on fixing the other problems!

 

[Bayleaf]

Gaswould Would the first procedure work on my 350 SL R231

 

[OneForTheRoad]

Gaswould Would the first procedure work on my 350 SL R231

Try it . My e350 didn't like it.

 

[dazblink]

Just a thought... Could it be possible that the auxiliary battery may have a malfunction causing my issue? I may be being a bit thick here but what does the auxiliary battery actually do?

 

[Gazwould]

Gaswould Would the first procedure work on my 350 SL R231

You can only try , older Mercs that first got the abomination function seem more amenable .

I know E Class W212 throw warnings .

 

[markjay]

Driving around with the Start/Stop disabled isn't an issue as such.

But Ideally it should only be done after the fault has been diagnosed and identified.

Otherwise you are running a risk of simply plastering over a different issue.

It is possible that the Stop/Start ECU was damaged by the jump start, in which case disabling it one way or another is a possible workaround.

But it is equally possible that other components that feed input into the Stop/Start ECU were damaged - e.g. the front SAM etc - so you don't know what other components may be malfunctioning.

If you don't want to take the car to a garage to get it properly diagnosed, you could get an iCarsoft scanner, get the codes read and noted, then remove the fuse, delete the codes and rescan. If the codes don't come back with the fuse removed, then you have
successfully isolated the faulty part. If the faults come back, you'll need to continue investigating. It's not a perfect solution, but it's the best diagnosis process you can carry-out DIY.

 

[dazblink]

Driving around with the Start/Stop disabled isn't an issue as such.

But Ideally it should only be done after the fault has been diagnosed and identified.

Otherwise you are running a risk of simply plastering over a different issue.

It is possible that the Stop/Start ECU was damaged by the jump start, in which case disabling it one way or another is a workaround.

But it is equally possible that other components that feed the Stop/Start ECU were damaged - e.g. the front SAM etc - so you don't know what other components may be malfunctioning.

If you don't want to take the car to a garage to get it properly diagnosed, you could get an iCarsoft scanner, get the codes read and noted, then remove the fuse, delete the codes and rescan. If the codes don't come back with the fuse removed, you have isolated the faulty part. If the faults come back, you'll need to continue investigating. It's not a perfect solution, but it's the best diagnosis process you can carry-out DIY.

Hi mate. Thanks for the reply. I do have an icarsoft 2.0 scanner. It currently reads 2 other faults which i also need to sort out (a possible thread for another day) but theres nothing coming up that is related to this.

The botched jump start initially left the car totally dead. I bridged the pre fuse SAM that is connected to the battery and i was back in business. I removed the SAM checked the fuses inside and the fuses were ok. After scratching my head for a while i realised it must have been because it was a module that was blown inside the SAM. I picked up a second hand SAM from a breakers, fitted it and removed the bridge. I fitted a new battery while i was at it. All seemed well except for a blown fuse in the radio which i sorted too.

It weren't until next time i was out that the ECO kicked in and then wouldn't start. Whilst stuck there at some traffic lights i tried disconnecting the battery and that seemed to reset it and the car started again.

I suppose it could be that the 2nd hand SAM has a fault? But do you know where the stop/start ECU is or is it part of the main ECU?

 

[merc07]

Out of interest, what actually happens to the stop start light if you remove the fuse or battery, does it just stay orange or go out completely ?

 

[dazblink]

Out of interest, what actually happens to the stop start light if you remove the fuse or battery, does it just stay orange or go out completely ?

I've not tried that yet. I'm planning on doing it tomorrow as a temporary fix so i will let you know if someone who knows doesn't get back to you in the meantime

 

[Gazwould]

Out of interest, what actually happens to the stop start light if you remove the fuse or battery, does it just stay orange or go out completely ?

Green then just goes out as per 9:44 .

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[markjay]

iCarsoft can show the state of the Stop/Start parameters. Might be worth reading the live data while the car is driven and stopped, to see if any of the parameters is showing implausible data.

 

[dazblink]

iCarsoft can show the state of the Stop/Start parameters. Might be worth reading the live data while the car is driven and stopped, to see if any of the parameters is showing implausible data.

Really? I've not seen that. How do i get to that?

 

[markjay]

Really? I've not seen that. How do i get to that?

It's in the live data. That's a screenshot from the Internet: