Emergency Run (Alarm 2420)
The ATLAS-COPCO-2420 (Atlas Copco Xc-series controller (Xc1004 / Xc2003 / Xc4004)) diesel fault code means: Emergency Run (Alarm 2420). This is a critical severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
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Common Symptoms
- Alarm 2420 shown on the Xc-series controller display
- Machine may shut down or refuse to load, depending on the alarm class
Probable Causes (Ranked by Likelihood)
- The condition named by the alarm: Emergency Run High
- Sensor, switch or wiring fault in the monitored circuit producing a false alarm Moderate
Step-by-Step Diagnostic Procedure
Identify which Xc-series controller your machine has FIRST (Xc1004, Xc2003 or Xc4004 — it is named on the controller face or in the machine documentation). The same alarm number can mean different things on different controllers, so the controller identity is part of the diagnosis.
On Xc4004: alarm 2420 = Emergency Run
Check whether an emergency-stop button is latched in — twist or pull to release, then reset the alarm. If no button is pressed, the controller may be missing reference voltage to the emergency-stop input, which means a wiring or contact fault in that circuit rather than a real stop.
This page is built from Atlas Copco's published Xc-series alarm table (linked below). For machine-specific procedures, use the manual for your exact unit — the table defines what the alarm is, not every model's repair steps.
Frequently Asked Questions
What does Atlas Copco alarm 2420 mean?
On the Xc-series controllers that use it (Xc4004), alarm 2420 is: Emergency Run.
How is the severity on this page decided?
Atlas Copco's published alarm table names each alarm but does not grade severity, so the rating here is inferred from the alarm's function (shutdown-class alarms rated higher than warnings and service reminders). Treat any alarm that stops the machine as serious regardless of the label.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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