Atlas Copco controller displays E030 Sensor Supply Fault / 5V Reference Error

Safety first: Disconnect battery negative before unplugging multiple sensors to avoid accidental shorts.

• Check controller diagnostics: Identify which sensor group is affected (e.g. pressure, temperature).
• Inspect harness: Look for pinched or rubbed‑through wires in the sensor harness that could short the reference to ground.
• Isolate sensors: Disconnect sensors on the affected reference line one by one, powering up each time, to identify which sensor causes the fault to reappear.
• Replace faulty sensor: Once identified, replace the shorted sensor with an Atlas Copco‑approved part.

If the fault persists with all sensors disconnected, the controller internal supply may be damaged and require replacement.