Q for Volvo geeks; Volvo D13 fault code; Mid 128 PPID 35 FMI 1 ?

this code popped on my dash, the truck is running ok, I delete it but reappears.
I have all fault codes downloaded on my Droid from this very useful link posted by Pablo UA for Volvo motors in "Trucks" section;
http://www.thetruckersreport.com/tr...een-wheelers/177140-fault-code-web-links.html

shows ERG flow too low ; Q; what sensor makes this readings?

 

Ok...thx!
But, does EGR valve have a sensor to read this fault? or the differential pressure sensor measures the flow and sends this fault to ECM ? I had problems before with this sensor and the 2 boost sensors clogged with carbon;

 

was bad EGR valve, I replaced it after I posted this last year; motor lost power , I made it slowly to Volvo, I was thinking needs in frame. This was the 2nd egr valve in 1.1 mil miles, the original lasted 800k miles.

 

This same low EGR flow code was popping again on my screen over past weeks. But only in colder weather bellow 30s F when i was north , as soon as i got south into Arkansas ,Texas in temps above 40s it stopped.
Searching for fix, i came across this old post on Mack forum ;

" There is some new info from Mack about this code. Its cause by moisture in Mass flow tube messing up sensor, this seems to happen in cold weather. The Mack dealer can call Mack One Call and they can give instructions on how to fix problem. I know it involves changing the engine thermostat and cleaning out the Delta-P sensor. You need to clear the code with stalk switch or the truck wont regen and then you have another problem. We got one here doing it as well."

Fault Codes

So, I removed the EGR sensor a coulple of times when the fault was active in cold weather , and found moisture , i shook it hard and few drops of water drained out of it. It fixed the fault for a couple of days in cold.
Im just posting this , if some of you get EGR flow codes in cold , check this before you waste money like myself on EGR valve or other expenssive parts,( it's easy to remove and clean it, 2×10mm bolts, ) . I don't know how moisture gets in, my egr cooler does't leak, i dont lose coolant, could be just from combustion perhaps diesel enrichead with water.