!!
critical HP

Error Code LED flashes Red four times and then White two times

Processor thermal protection due failure or blockage in fan.

? What Causes This

Blocked air intakes, malfunctioning processor cooler fans (or their connections).

How to Fix It

  1. Check for airflow clearances near vents and fan operation.
  2. Validate proper installation of heat sink and clean if clogged; replace faulty fans.

Source: page 79 of the official manual

From the manual

Manual page 79 — HP error LED flashes Red four times and then White two times

This error code appears in:

HP Prodesk 400 G3 Desktop Mini PC