W220 S320cdi no crank, display defective,esp fault

[Grahamkendall]

Good afternoon fellow 3 pointed star enthusiasts.

I have a rather nice s320cdi that I am having issues with.

This has been ongoing for some time and is very annoying. When I go to start the car I get display defective and esp fault message coming up...this in turn won't allow you to crank. So overcome this I have been opening the bonnet and giving the behind drivers side (UK) fuse box/ECU/Sam or whatever else is in there a thump. You can immediately hear relays click and a higher pitched noise that sounds like the fuel pump kicking in, it then starts no problem after cycling the ignition.

The same needs to be repeated after nearly every time you switch it off.

Battery is brand new. It has clearly had a replacement negative cable at some point as it's a narrow gauge halfrauds number. But to me it seems like something is awray in that fuse box hence the technical tap.

If any of you bright sparks have any ideas please help!

 

[mattkh]

I do not have a S320 cdi or access to any wiring diagrams
With the key out of the ignition, take the cover off the fuse box.
Then push down all the relays you can see.

 

[Grahamkendall]

I do not have a S320 cdi or access to any wiring diagrams
With the key out of the ignition, take the cover off the fuse box.
Then push down all the relays you can see.

I have tried that...it's very strange. It is only when you give it a robust tap or lightly hit it that it responds. It's clearly something in that box but I can't figure out what...I'm going to pull everything it and try. It seems worse when weather is getting colder for some reason

 

[mattkh]

Thanks.
What year is the S class..?

 

[mioba]

clearly something loose, cold weather things contract so any loose connection is becoming more loose.
Unplug battery.
Replace Halfords' cable with gen MB part. Make sure all contact points are wire brushed and clean and tight.
Is everything thats on that circuit (from that fuse box)dead until a wack, or is EVEYTHING dead.

 

[alexanderfoti]

Soudns like a bad relay in the Sam module. Tap each one until it works, then replace