Cummins/Onan Energy Command 20 — Troubleshooting
Testing & diagnosis · EC-20 controller
For the Cummins/Onan Energy Command 20, from the Cummins/Onan service manual.
Applies to: Cummins/Onan HDKA, Cummins/Onan HDKB, Cummins/Onan HDKC
Procedure
- Check whether the genset operates correctly from the genset controls.
- Confirm the correct connection diagram (Figures 5-7) was used, then check EC-20 wiring connections.
- Confirm that the correct voltages are present on each terminal.
- Check all terminal connections on both ends of the wiring harness; verify connectors are properly joined.
- Repeat the TEST SYSTEM procedure.
Full service-parts list: Cummins/Onan HDKA →, Cummins/Onan HDKB →, Cummins/Onan HDKC →
Source: Cummins/Onan service 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.