2007 ce with egr dt466. Runs fine. Defaults to 3rd gear I believe. Wont connect with service maxx, Allison, meritor, or diamond logic. All fuses and harness checked ok. Both terminating resistors are 120 ohms when taken off. Have 60 ohms at all modules. All powers and grounds good and load tested at all modules. Only signs/symptoms are trans temp light on and check electrical light on. Starts and runs great just no power due to being in limp home from trans.any ideas?
Since you have not communications and you checked the J1939 circuit and the ohm readings are right, that all sounds good. What stands out it the "Check electrical" light. Check your fuses in the battery box and all the connections along that particular wiring harness to the relays it feeds. It should provide power to the ECM, TCM, and IDM relays. Those are the relays right above the engine on the fire wall..
Thanks guys. I found it. the TCM power feed was giving 12 volts but I load tested the wiring and the voltage drop was pretty significant. Someone had probed this wire before and it corroded inside the insulation.