2006 Kenworth, engine cranks does not start, have the three B+ at pins 48, 52, and 53 B- at 63, 65, and 67 good, also have the ignition B+ at pin 70. Engine ECM cannot be communicated with via my scanner. Key on, the solenoid for the air controlled fan clutch cycles on and off. The data link tests good at 60 ohms. Found an extremely poor battery negative connection at the starter, so bad that the engine stopped cranking at all until it was repaired. Had this exact no start one month ago, disconnected the two harness plugs from the ECM, plugged them back in and the engine started.
Sounds like you may have a bad ecm. Does the check engine light come on with the key on?
Give us a clue - Serial Number..?
Sounds like ecm failiing. I’ve had them do that where I unplug the ecm connector then reconnect and I can communicate with ET for a minute or two again before I lost communication. The truck will start for a few seconds after reconnection too.
Check for out puts of ecm injectors pulse reference voltage
I would deff check out puts on ecm. Bad grounds kill components. But also what are you checking ur powers and grounds to ecm connector with cause led test lights with screw u up. Load the circuits with old school test light or a head light.
I agree sounds like ECM. have had a couple over the years do that if you have ET watch the status screens usually the parameters show and not show on a regular basis BUT having said that have you checked for codes or FUEL pressure? Also agree on not using LED test lights on power circuits Mark
Did you locate the problem?