Cummins/Onan — Remote Communications Tests

Testing & diagnosis · Digital Display communications ports

From a Cummins/Onan owner's manual covering: 1.5HJBAA, 2.0HJBAA, 2.5HJBAA, 3.0HJBAA. Check it applies to your exact model before use.

Browse Cummins/Onan generators & specs →

Procedure

1. Connect the batteries and check for 12 VDC across the Inverter-Charger terminals.
2. Check for 12 VDC between pins J1-3 (B+) and J1-4 (B-) and between J2-3 (B+) and J2-4 (B-). Replace the Inverter-Charger if no voltage.
3. Check the Display wiring harness for 12 VDC between pin receptacles 3 (B+) and 4 (B-); repair or replace the harness as necessary.
4. Plug a Digital Display into a port with 12 VDC between pins 3 and 4; replace a Display that does not wake up when any key is pressed.
5. If 'COMMUNICATIONS LOST WITH MAIN CONTROL' appears, test with harness 541-0919 (25 ft) or 541-0932 (50 ft).
6. If the test harness works, repair or replace the vehicle harness; if the warning persists, connect a known-good Display, then replace the Inverter-Charger if communications cannot be established.

Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

More Cummins/Onan repair guides →