EGR error codes P040D00 & P040C00 (temp. sensor)

[n10n]

Makes me wonder if this is the design to quickly warm up coolant entering into cabin heat exchanger....

Good point, although I would vote for just getting engine up to temp - quick coolant heat up is not necessary in summer

I didn't see the peak at the end

Now that you mention I probably (almost) idled for some time at the end of my sample drive as I went to fill her up but all the pumps were vacated.

now the positive/negative transition might have got the explanation.

I still don’t really grok this. Afaiu EGR coolant changeover valve and the actual EGR valve are separate, and I don’t see the point unless zero (off position) is somehow half open, and the neg/pos would be fully closed/open.

PS. Apologies @xcelrec for slightly deviating from your issue

Yes, apologies, completely my fault! Can’t help it when I see some interesting data and I do like open discussions around technical topics!

 

[xcelrec]

PS. Apologies @xcelrec for slightly deviating from your issue - but it's still about your sensor and how to take advantage of it

Yes, apologies, completely my fault! Can’t help it when I see some interesting data and I do like open discussions around technical topics!

Don't apologize! Even though I only understand half of what you guys are writing, its super interesting. So please, keep discussing here If you want !

 

[n10n]

Now I do see the behaviour also in my logs - haven't paid attention on that although tried to evaluate the EGR cooler blockage by recording everything related I could imagine.

View attachment 212102

I don’t as of now have any logs of IDE11872 but that indeed looks like exhaust temperature range, taken right off exhaust manifold.

I just looked at IDE07727 - coolant temperature at radiator outlet and it is <38° in my sample trip. I could not get how would it be possible to get 300° or so exhaust down to <50° in EGR cooler using coolant without some major pressure plays… but because radiator is so efficient I guess it just works out .

I will humbly cancel out my suspicions and agree IDE07729 measures air temperature.