W221 S350 not starting (doesn’t even try) after service.

[DSK]

27/03/2024

Tried disconnecting the battery, leaving it for a suitable time and then reconnecting. This did not help either.

It’s unlikely I will get to speak to Nick at Mb Centre until the other side of Easter now.


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[krsebest]

27/03/2024

Tried disconnecting the battery, leaving it for a suitable time and then reconnecting. This did not help either.

It’s unlikely I will get to speak to Nick at Mb Centre until the other side of Easter now.


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Have you tried jumping the car or putting on charger when trying to turn it on? This seems to always work for me when this no start comes up (even though my battery is brand new and battery voltage perfectly fine at over 12.5V)

 

[DSK]

Not connected to a charger now.
This is a brand new varta battery yet again for belt and braces but, the car doesn’t drain the battery. It’s at 12.9v at moment.

I have previously (before it went into the garage) tried it with a charger to no avail.


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[V6Matty]

I can’t remember if you said they’ve looked at the BCM (battery control module) on this? Going back a few years before I got the 212 I have a Peugeot 508 RXH, two years old and decided that it just didn’t want to start after a few weeks of ownership, would get in and press start and would get all sorts of weird things happening but no start (didn’t even try), the Peugeot garage chief mechanic had lucky seen it just once before and instantly said BCM failure preventing drive authorisation, however, it wouldn’t should as a code or even log an error, the previous time he’d seen it they spent two months chasing it down with Peugeot HQ and thousands in parts and more hours than they counted.

 

[DSK]

@V6Matty

I doubt it as nothing other than a new battery or, anything around it has been mentioned.

Is this that thing in above posts a battery/ignition relay module? I wonder if this is that thing mentioned in the Auto Elite fix?

I’ll add it to the growing list of things to check.

Everyone seems to have changed everything but, first I’ve heard of this. Would be epic if this part solves it and helps many others.

I’ll see if I can track down a new one. Worth a punt at this stage and at worst it will be a Mercedes genuine new parts car at worst. Not a lot one can do other than open the wallet a despite me offering an open wallet no mobile specialist is interested.


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[V6Matty]

looks like it might be what was referred to, for the cost it's got to be worth a punt.

@V6Matty

I doubt it as nothing other than a new battery or, anything around it has been mentioned.

Is this that thing in above posts a battery/ignition relay module? I wonder if this is that thing mentioned in the Auto Elite fix?

I’ll add it to the growing list of things to check.

Everyone seems to have changed everything but, first I’ve heard of this. Would be epic if this part solves it and helps many others.

I’ll see if I can track down a new one. Worth a punt at this stage and at worst it will be a Mercedes genuine new parts car at worst. Not a lot one can do other than open the wallet a despite me offering an open wallet no mobile specialist is interested.


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[DSK]

Just seen this and perhaps I was wrong above, this is the battery control module ;

The first one is coming in at £300 new on eBay and no doubt this will be punchy too new, for a punt. Hard to trust these used as they may be from non starting cars. Certainly added to the parts darts list.


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[V6Matty]

Just seen this and perhaps I was wrong above, this is the battery control module ;

The first one is coming in at £300 new on eBay and no doubt this will be punchy too new, for a punt. Hard to trust these used as they may be from non starting cars. Certainly added to the parts darts list.


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Sorry yes the previous was the starter relay not the bcm, this doesn’t look quite right either,

 

[DSK]

I had a closeup on the part and it’s listed as a battery control module

If this is not what you meant, would you be able to share the part you are thinking of?

I’m not fan of buying these used but, for a punt I will get the above two parts used for a punt. I also think the auto elite thread fix must have been one of those 4 prong relays if it was a sub £125 fix, but, I cannot find any results for an ignition relay.


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[malcolm E53 AMG]

Have you thought about using an auto electrician as the fault appears to be in the CAN bus system

Car Diagnostics Leicester, Auto Electrician Leicester

Looking for Car Diagnostics Leicester? Please call us on 0116 298 2576 for immediate support.

www.nmautoelectricsleicester.co.uk

 

[DSK]

Have you thought about using an auto electrician as the fault appears to be in the CAN bus system

Car Diagnostics Leicester, Auto Electrician Leicester

Looking for Car Diagnostics Leicester? Please call us on 0116 298 2576 for immediate support.

www.nmautoelectricsleicester.co.uk

Yes thanks for this and I will make a call. I was hoping that MB centre would have contracted one if they can’t do it, surely that’s common sense. I just need someone to do what they need and sort it.

Let’s see what happens other side of Easter.




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[V6Matty]

I had a closeup on the part and it’s listed as a battery control module

If this is not what you meant, would you be able to share the part you are thinking of?

I’m not fan of buying these used but, for a punt I will get the above two parts used for a punt. I also think the auto elite thread fix must have been one of those 4 prong relays if it was a sub £125 fix, but, I cannot find any results for an ignition relay.


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Ah now you zoomed in that does look like it’s the right thing, when I was looking at other generic pictures it didn’t look the same, so that’ll teach me to look closer in the future

 

[DSK]

I’ve been doing some digging on battery control module, on the 2011 it does not exist.

My understanding is on cars with 2 batteries, there was a battery control module. On cars with one massive battery under the bonnet, the battery control module is replaced with battery sensor as shown below taken from a generic picture.

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[tode]

I’ve been doing some digging on battery control module, on the 2011 it does not exist.

My understanding is on cars with 2 batteries, there was a battery control module. On cars with one massive battery under the bonnet, the battery control module is replaced with battery sensor as shown below taken from a generic picture.

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I'm not quite sure what you mean . . . you do have 2 batteries, don't you ?

 

[DSK]

I'm not quite sure what you mean . . . you do have 2 batteries, don't you ?

No, only the one battery and MB centre confirmed. Not all w221s have 2 batteries.


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[ajlsl600]

Daft as it sounds even though all should be well as the car hasn’t been used since Nov 2023 and I can’t vouch for how it was treated/driven when the mechanics had it, I’m going to take it to the local petrol station, check tyre pressures and reset the run flat indicator first, then give the garage a call tomorrow.


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My money is on failing wss. They are made to a crap std these days I had tyre press warnings and esp lights was wss. Get a decent code reader, look at live data for wss see if all are same or.
Icarsort v2, 3 does this.

 

[tode]

No, only the one battery and MB centre confirmed. Not all w221s have 2 batteries.


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If you have a 2011 Bluetec (which I believe is the case), then you will certainly have two batteries.

I really think you should find another garage.

 

[DSK]

My money is on failing wss. They are made to a crap std these days I had tyre press warnings and esp lights was wss. Get a decent code reader, look at live data for wss see if all are same or.
Icarsort v2, 3 does this.

Would make sense as if it’s a wss. Previously the car has driven without a glitch despite the issue. On the last drive the ESP and run flat remained inoperative along with any gizmos associated with it like speed limiter and cruise.

I don’t think anyone has confirmed if a wss can stop a car from cranking and starting. Would be great if the fix is new wss all round.

my icarsoft wouldn’t connect for some reason.


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[DSK]

If you have a 2011 Bluetec (which I believe is the case), then you will certainly have two batteries.

I really think you should find another garage.

It is a 2011 S350 bluetec.

I have reached out to auto elite, they will confirm after Easter if they can come out.

If anyone here knows what they are doing and wants to see if they can help I will pay them.

Contacted a few mobile specialists in the midlands and despite me saying charge whatever you need for travels etc - they declined.

The car is beached and recovery is not an option when the car is in this state. The last recovery driver confirmed this.

Very little I can do other than open my wallet.

 

[ajlsl600]

Would make sense as if it’s a wss. Previously the car has driven with a glitch despite the issue. On the last drive the ESP and run flat remained inoperative along with any gizmos associated with it like speed limiter and cruise.

I don’t think anyone has confirmed if a wss can stop a car from cranking and starting. Would be great if the fix is new wss all round.

my icarsoft wouldn’t connect for some reason.


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Try another icarsoft if that fails u may have a system reporting issue. When it works you will see which, if any, wss is misbehaving I don't believe a wss will trigger a no start situation, tho I think cruise and speed limiter all look wss input and I wud not be surprised if one iffy wss caused those issues.
It's beyond me why the ****** ecm cannot average the remaining working wss, ie 3 and carry on as normal whilst alerting you the the one faulty sensor. I thought electronics were built to be logical, but in fact they, it seems are designed to send you and ur wallet to the dealers!!!