2013 CLS 350 AMG heating problems

[Brockhillbob]

Hi - I have a 2013 CLS 350AMG which has developed the following fault, and Im looking at clues as to whats wrong please - bear with me, its a bit odd!

On a cold morning (Birmingham UK winter) I get:
ECO start/stop led shows green for a few seconds then goes off
Drive a few miles, the temp guage moves correctly and I get hot air in the cabin
After say 15 mins, the temp guage falls to zero and I get cold air in the cabin

If I stop the car and restart, the Eco led shows green and stays on
The temp guage works as normal, and I get hot air back in the cabin

Ive lived with planning a short stop in a bus stop I use regularly, but thats no longer amusing

Any clues as to whats going on please?

The rest of the car is absolutely perfect, I just want to sort this annoying fault

Thank you!
Bob

 

[E55BOF]

Does everything remain normal after the stop and restart? If you carry on driving without the stop, does the system stay in the faulty mode, or eventually sort itself out?

 

[Brockhillbob]

Does everything remain normal after the stop and restart?

Yes, after that stop / start, everything works as normal
I dont get any warning lights on the dashboard

 

[E55BOF]

Your problem is more than odd, it's bizarre. It has to be electrical.

Have you had the codes read? That may not help, though, unless you can get it done while it's actually doing it - ie, without stopping the engine - and that may be problematical.

(I have a gremlin in my 2013 CLS350 SB; roughly every thousand miles, within a mile of a cold start the transmission seems to go into something similar to, but not the same as, limp mode. Stopping and restarting the engine sorts it every time. I've had the codes read on Star; nothing. The suspicion is that it is a transient fault related to the electroplate in the gearbox.

I have an iCarsoft MB II code reader, and I now carry it in the car, with the cable end permanently plugged into the OBD port and the loom wound round the steering column shroud; when it happens again, I'll plug the loom into the unit while keeping the engine running and see if there's a code then. Typically, the gremlin knows I'm after it and it hasn't now appeared for some time...).

If there are no fault codes showing on Star on yours, you might like to invest in an iCarsoft or something similar and do the same; at least your gremlin is consistent...

 

[Brockhillbob]

lol! we are like minded, I also have a code reader permanently plugged in but like you ,I dont get any codes reported
Ill try and find a local electrical speciailst who might have a more sophisticated diags tool

Thank you - Ill let you know how it goes
Bob