[grantbp]

Hi,
I have an error i am struggling to resolve.
Coolant temperature sensor upstream of low temperature EGR cooler- error is triggered when a difference between the coolant sensor and egr low temperature sensor is seen.
- replaced egr coolant temp sensor x 2
- replaced main coolant temp
- at temp main coolant temp is reading 85 degrees C and EGR low temp sensor is reading 30.
- removed EGR temp sensor and cable in placed in cup of hot water...temp shot up to 70 degrees C.(this would prove operation of sensor is fine.
-When car is up to temp...EGR cooler is very hot to touch...coolant hoses hot to touch...however hose from cooler down to temp sensor is cool.
-My problem would appear to be that the sensor is reading what it is seeing and the coolant is not hot at that point...never gets above 30 degrees C.
From the coolant system flow diagram it would appear the coolant from the low temperature rad side flows past EGR temp sensor, up the hose(see pic attached) into egr cooler, cools the gas then flows into engine block???
I am curious what the operating temp of the low temp side should be??
The error happens on a cold engine also almost instantly.
I was thinking a blocked egr cooler, or faulty changeover valve or coolant pump.
But if the flow is going past the temp sensor before it goes into EGR cooler, something further back on the coolant line could be blocked??
Any help or ideas or how to test would be welcome my knowledge of this system is very little

[leyeti77]

Hi
did you solved this ?
Where did you get the pict with yellow parts shown ?
Thx
PS : Are you aware of EGR program change, since they are faulty between March 2011 and 2016

[grantbp]

Hi,
Yes I did get it fixed.
The picture is from BMW newtis.info has service manuals for all models.
You will really a copy of Rheingold or detailed diagnostic software to properly trouble shot this issue.
Granted hindsight is a great thing..but with Rheingold I was able to cycle the pump and the changeover value. Turns out the changeover valve was not operating.
It must have been stuck in open position meaning that the cool side of the rad coolant system was constantly flowing to the point at which the EGR temp sensor was at,therefore the thermostat would always be reading much lower than the main engine coolant temp sensor.
Got a second hand changeover valve,installed and get temp rose with the main coolant temp...you will see it drop when the changeover valve opens but this is expected and does not give an error.

[grantbp]

I wasn't aware of the faulty EGRs...was there a recall or anything???