Engine management light on

[ambjoinery]

C350CDI ESTATE, MY 2011

HI everyone. I have the engine management light on, no loss of power, all electrical consumers work ok.
The car has detachable towbar, with the dedicated towbar wiring kit fitted to the Rear SAM unit. The only potential issue I've noticed is when engine off (ignition key removed) ,when I plug caravan electric cable into car 13 pin tow socket, the rear tail lights ,lluminate. When I start engine, the rear tail lights go off.
I've performed a scan with my icarsoft MB v3 see attached photos for information. When I clear fault codes they return after a few days, or approximately 20 miles. Can anyone suggest the best course of action?
Thanks

 

[ambjoinery]

Sorry, see attached photos for i carsoft information

 

[ambjoinery]

Apologies again, here's the link for the i carsoft images

Album — Postimages

postimg.cc

 

[ambjoinery]

Apologies again, here's the link for the i carsoft images

Album — Postimages

postimg.cc

Hi guys. I've just done another i carsoft scan, and it's coming up with another fault code, in addition to the previously posted fault codes! ( see attached photo).
Dose anyone have a rear SAM wiring diagram, for a 2011 S204 , so I can identify relay 1 , curcit 15.

https://i.postimg.cc/B6qw4Wcj/4.jpg

 

[W1ghty]

Hi guys. I've just done another i carsoft scan, and it's coming up with another fault code, in addition to the previously posted fault codes! ( see attached photo).
Dose anyone have a rear SAM wiring diagram, for a 2011 S204 , so I can identify relay 1 , curcit 15.

https://i.postimg.cc/B6qw4Wcj/4.jpg

On the right hand end of the drivers side dashboard , there should be a fuse chart folded up that may list the relays (at least that’s where my W211 E320 fuse chart is

 

[ambjoinery]

On the right hand end of the drivers side dashboard , there should be a fuse chart folded up that may list the relays (at least that’s where my W211 E320 fuse chart is

OK, thanks. I'll have a look.

 

[Ted]

Circuit 15 is ignition live. Usually a black wire.

 

[ambjoinery]

Circuit 15 is ignition live. Usually a black wire.

Thanks Ted. When I get time, possibly at the weekend, I'll have a look

 

[ambjoinery]

Update. Checked the rear SAM wiring curcuit 15, i couldn't see any wiring issue. Checked the westfalia dedicated towing electrical loom, i couldn't see any issues. I then checked the car 13 pin socket and sprayed with WD40, & the caravan lead towing plug. I then plugged lead into car socket, and rear car tail lights DIDN'T illuminate. I then Did a scan, with the icarsoft, no rear sam fault. However another new fault appeared -:

DCU_RR - Right Rear door(N69/4)
Fault I (1)

990915 . State: Current and Historic
The Output For Actuator Motor " Additional Door
Lock'' Has A Malfunction. There Is A Short Circuit
To Positive Or An Open Circuit.

Thing is right rear door lock, and all other 3 doors are working OK!
Did approximately 20 miles yesterday, 3 separate journeys, and up to now ,no EML on.
Has anyone any suggestions? I probably won't use car until the weekend, so I'll monitor if the EML stays off
Link to photos

Album — Postimages

postimg.cc

 

[W1ghty]

Update. Checked the rear SAM wiring curcuit 15, i couldn't see any wiring issue. Checked the westfalia dedicated towing electrical loom, i couldn't see any issues. I then checked the car 13 pin socket and sprayed with WD40, & the caravan lead towing plug. I then plugged lead into car socket, and rear car tail lights DIDN'T illuminate. I then Did a scan, with the icarsoft, no rear sam fault. However another new fault appeared -:

DCU_RR - Right Rear door(N69/4)
Fault I (1)

990915 . State: Current and Historic
The Output For Actuator Motor " Additional Door
Lock'' Has A Malfunction. There Is A Short Circuit
To Positive Or An Open Circuit.

Thing is right rear door lock, and all other 3 doors are working OK!
Did approximately 20 miles yesterday, 3 separate journeys, and up to now ,no EML on.
Has anyone any suggestions? I probably won't use car until the weekend, so I'll monitor if the EML stays off
Link to photos

Album — Postimages

postimg.cc

How old is the car battery , MB’s hate low voltage .

 

[markjay]

I don't see how any of these faults can trigger EML?

EML came to be as a result of a requirement to let the driver know that there's an issue with the car's emissions. It was later expanded to include some other engine-related issue. But none of the fault codes relate to engine or transmission?

Obviously, the logged fault codes need to be addressed, but I don't think that fixing these issues will extinguish the EML?

 

[ambjoinery]

How old is the car battery , MB’s hate low voltage .

The car battery is the original MB ( Varta ) Post stamp wk 24/11 . I've never had a flat battery, car is often garaged from sun evening to Fri or Sat day, never refused to start. Auxiliary battery voltage was showing 13.5 V . After owning car since July 2016, I'm tempted to renew battery.

 

[ambjoinery]

I don't see how any of these faults can trigger EML?

EML came to be as a result of a requirement to let the driver know that there's an issue with the car's emissions. It was later expanded to include some other engine-related issue. But none of the fault codes relate to engine or transmission?

Obviously, the logged fault codes need to be addressed, but I don't think that fixing these issues will extinguish the EML?

Hi markjay. Can you elaborate on your paragraph 2, "
EML came to be as a result of a requirement to let the driver know that there's an issue with the car's emissions. It was later expanded to include some other engine-related issue. But none of the fault codes relate to engine or transmission? "