Malfunction Light

[2017 Mercedes Benz C350E]

Hello there i own a 2017 C350e Estate Amg line and i would like to know about this malfunction light, you see since the start of the owner ship of this car, a malfunction light has always been popping up and with the replacement of a new exhaust it had lessened it popping up. The problem is the car has been remapped by a previous owner and we have gotten some specialist to reprogram the ecu back to stock. and the malfunction light keeps on popping up when scanning the ecu even with a powerful one which scan each individual thing further than the base codes it wouldn't show a single thing it would still show malfunction but no code. It just says cooling and that it nothing specific.

However my theory is since the cat was full of soot because of a blown engine (long story from copart) perhaps it heating up trying to burn it might have transferred the heat from the cat all the way to the battery since well metal does transfer heat. and would heat up the battery causing some sort of cooling issue.

Honestly it runs perfectly fine as well

Please can you help me understand what this malfunction might mean

Thank you

 

[mioba]

Frin what you have said you need a decent garage with a good code reader. A merc indy.

Where are you based.

Not often a merc needs a new exhaust.

 

[Srdl]

Sorry, not clear what malfunction light you mean but guessing it is something to do with battery temperature?

On a 6 year old Merc, that could be many things and the early Merc hybrid technology was very unreliable. You do need a Merc Specialist, who has the correct scanning technology and, preferably, experience with hybrid systems.

 

[Botus]

so its a tractor engined car (kind of important for diagnosis to give us all the detail) ? its been tampered with, and now the merc designed to fail to time EML has come on everyone is confused?


its not really complex - just few believe the truth

this whole thread should help give some clues - especially posts #27 and #30

Xentry Diagnostics Value 751 - Factor for adaption of component 'NOx sensor upstream of SCR catalytic converter'

Edward. Again, an interesting post and perspective. My understanding is that it is just much more than the sensor that requires replacement. The ECU that goes with it is pre-determined to software which requires to be updated and coded to the whole engine, powertrain, gearbox and SCR system...

forums.mercedesclub.org.uk

 

[Larkone]

engine remapped - odd thing to do on a 2.0 petrol/hybrid
engine back to stock
new exhaust
new engine
on going EML - no codes apparently but what about live data?

Seems to be a lot of change with little information as to when each took place or what else has been done and who did the work - do warranties apply?

A case of 'something' broken - what 'something' needs to be fixed?

 

[Srdl]

so its a tractor engined car (kind of important for diagnosis to give us all the detail) ? its been tampered with, and now the merc designed to fail to time EML has come on everyone is confused?


its not really complex - just few believe the truth

this whole thread should help give some clues - especially posts #27 and #30

Xentry Diagnostics Value 751 - Factor for adaption of component 'NOx sensor upstream of SCR catalytic converter'

Edward. Again, an interesting post and perspective. My understanding is that it is just much more than the sensor that requires replacement. The ECU that goes with it is pre-determined to software which requires to be updated and coded to the whole engine, powertrain, gearbox and SCR system...

forums.mercedesclub.org.uk

No, petrol/electric

 

[Larkone]

Found this online regarding that vehicle
Powertrain
Hybrid heater booster failures are common, preventing the car from starting, and causing the red high voltage battery warning light to come on. The reason for this is water entering the module, which is located in the offside wheelarch.

The M270 petrol engine can suffer a failed crankcase vent valve, which will bring the engine light on. The water pump and thermostat can give trouble, also illuminating the engine warning light.