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Home›Repair guides›Cummins/Onan›Engine Does Not Crank in Manual Mode - Diagnosis and Repair

Cummins/Onan — Engine Does Not Crank in Manual Mode - Diagnosis and Repair

Testing & diagnosis · PowerCommand 2100 base board / starting circuit

From a Cummins/Onan service manual covering: QSX15, QSX15-G8, QSX15-G9. Check it applies to your exact model before use.

Applies to: Cummins/Onan DFE, Cummins/Onan DFEJ, Cummins/Onan DFEK, Cummins/Onan QSx15, Cummins/Onan QSX15-G9 engine

Before you start

  • Accidental starting can cause severe personal injury or death; disconnect negative (-) battery cable with insulated wrench.
  • Set generator set to off mode before disconnecting/connecting harness connectors.

Procedure

  1. Verify power to control: Control Alive indicator should be flashing on base board.
  2. Clean battery cable terminals and tighten connections using an insulated wrench.
  3. Remove F4 and check continuity; if open, replace with same type/amp rating (5 Amps).
  4. If F4 OK, remove connector P7 and check B+ at P7-1 to P7-4 and GND at P7-5 to P7-8.
  5. If B+/ground missing, isolate to harness and TB BAT terminal on engine block.
  6. If B+ and ground OK, base board may be defective; cycle power by reconnecting P7.
  7. Confirm calibration part number matches serial plate; re-enter calibration file if needed.
  8. With E-Stop not activated, remove P1 and check continuity between P1-1 (ESTOP-NC1) and P1-2 (ESTOP-NC2).
  9. With S12 in Manual, remove P1 and check continuity from P1-6 (MAN) to P1-9 (GND).
  10. Remove P3 and check continuity from P3-9 (MAN RUN/STOP) to P3-10 (GND); if none when pressing button, replace front membrane panel.

Tools required

Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.

Specs & values

  • F4 fuse: 5 Amps
  • Control Alive indicator flashes once every second when properly calibrated

Full service-parts list: Cummins/Onan DFE →, Cummins/Onan DFEJ →, Cummins/Onan DFEK →, Cummins/Onan QSx15 →

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.

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