It’s been a while since I posted, changed jobs and everything new shop, we towed in a cascadia daycab 2014 dd13 yday for a no start no crank issue, it just clicks when trying to start, it’s an auto shift dt12 transmission. the starter was changed, the ignition was changed, and the def light was flashing low even when full so the def pump assembly was also changed, at this
Shop they use a diagnostic program called jaltest which I hate since I’m used to diagnostic link, we swapped ecu’s with another same truck and still no luck it just clicks, it does not start when the starter is bypassed either, I checked and there is no signal coming to the solenoid wire so I’m assuming the ecu is blocking it? All relays and fuses were checked and there are no codes, however here’s where it gets interesting, the transmission display started showing F for fault, also the diagnostic program will not connect to the transmission module and says there’s a communication error even tho it connects to all other modules no problem which makes me think the Transmission ECU is the problem, I retrieved the codes from the trans display instead and it shows codes 21, 25 and 35, 36 but each one randomly, these also point to the trans ecu, so apart from no signal at the starter, the def light flashing, and no connection with the program, what else could it be? Am I on the right track? Any advice? Where do I go from here?