Quote:
Originally Posted by sgrice
I don't know specifically where the sensor is located that gives the menu 07.00 temperature. I also don't know if there is a sensor that specifically gives EGR coolant temperature. Certainly I couldn't find such a temp in the PDF document noted above.
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The coolant temperature sensor is mounted on the intake side of the cylinder head. The coolant in the M57 flows through the thermostat to the exhaust side, over to the intake side and then out. The temperature shown in the hidden menue is from that sensor.
There is no EGR coolant temperature. There is however a sensor for the exhaust fumes after the high pressure EGR cooler. Our HP EGR has basically 2 tracks: part of the fumes always get cooled and part of the fumes go straight through. The DDE achieved the desired temperature by activating a valve that mixes the two in different ratios. I'm under the impression that there no such thing with the LP EGR since it's only activated once coolant temperature is above a certain temperature.
I believe the bypass in the HP EGR is there not so much to regulate temperature under regular driving condition but to facilitate warmup.
You can read more here, if interested:
https://drive.google.com/file/d/0B1e...ew?usp=sharing