B0508
New Member
Started with DEF/emissions derate codes. Machine was running but derated.
Found broken wire between ECM J1 and SSR relay circuit. Repaired wire and regained power on pink wire feeding DEF-related modules.
Now machine is a no-start.
Current findings:
I have NOT located the SCR/DEF controller yet. Does anyone know exact location on D85PX-18 serial 22042?
At this point I feel like I’m missing something simple.
Found broken wire between ECM J1 and SSR relay circuit. Repaired wire and regained power on pink wire feeding DEF-related modules.
Now machine is a no-start.
Current findings:
- CAN resistance checks good at ECM J1/J2 (~60 ohms)
- CAN voltages appear correct
- Checked NOx sensor circuits
- Unplugged both NOx sensors
- Tested sensor on large SCR can and DEF tank module
- Reduced active codes significantly following troubleshooting
- Harness has been double checked
- Following Komatsu service manual troubleshooting tree
I have NOT located the SCR/DEF controller yet. Does anyone know exact location on D85PX-18 serial 22042?
At this point I feel like I’m missing something simple.
