Truck Repair: 99 freightliner ecm

Question
I am working on a 99 freightliner with an ISM engine. It will run for hours and sometimes days then die and not restart. I have pulled the harness for the ecm and ohmed and checked all the wires I can and can find nothing wrong. I have the following codes. Pid 168 with a flash code of 441 sid 232 and 251 with a flash code of 434. Can you offer any help. right now it wont fire at all. last time out it ran for five days before dying. Thank you.

Answer
Found that code 441 is unswitched battery supply circuit. So that will be the wire going directly from your battery to the ecm should be a fuse in it around the battery area.
Code 434 is the same code So definitely have something wrong in the battery power to the ecm. Never have worked on a ism in a freightliner but have worked on one in a international and if you follow the ecm power wires up to the ecm around the engine area was a weather pack connector and our international would do similar to what you have. it would run great for awhile the stop running what we found was that weather pack connector would lose contact so we would bypass it and solved all of our problems.