Generator will not start, controller shows E001 and immediately aborts cranking

Safety first: Ensure the generator cannot start unexpectedly. Place the unit in OFF on the Atlas Copco controller, isolate battery negative if working inside the control panel, and keep clear of moving parts.

• Check emergency stop button: Locate the red E‑STOP on the generator enclosure or remote panel. Turn or pull to reset. Confirm the E001 code clears on the Atlas Copco controller.
• Inspect safety chain: On the controller I/O diagram, identify the safety loop terminals (often labeled for E‑STOP, low oil pressure shutdown, high temp shutdown). Verify all jumpers and field wires are intact and tight.
• Test emergency stop switch: With power isolated, remove the E‑STOP switch from the panel and test continuity with a multimeter. It should be closed in the reset position and open when pressed. Replace if readings are inconsistent.
• Check external shutdowns: If connected to a fire alarm or remote stop, verify those contacts are not open. Temporarily bypass (for test only) at the terminal strip to confirm the generator starts.
• Controller reset: After correcting the fault, clear alarms on the Atlas Copco controller (Alarm Reset key or menu) and attempt a manual start.

If the E001 persists with all safety devices verified, the issue may be in the controller input board or wiring harness and should be diagnosed by an Atlas Copco service technician.