What a great forum! I recently acquired my FIL's E320 Bluetech (OM642) with 230k miles and am trying to get it tuned up. This is my first diesel so I am drinking from a fire hose. An oil leak appears likely to be the oil filter housing gasket (oil cooler has been addressed), so that is on the to do list.

It also has a check engine light and my generic code reader is pulling:
P0544 - Exhaust Gas Temperature Sensor Circuit
P2000 - NOx Trap Efficiency Below Threshold

Is there any value in buying a MB specific code reader? Looking at the iCarsoft MB II. Or am I getting all the info I can get?