Error 0021-0001-0001Medium Severity

Drop detector sensor malfunction, error status or state

Last updated: February 22, 2026

Severity:Medium Severity

Affected:0 models

DIY Fix:Possible

HP Z9+ System error: 0021-0002-0017

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What This Error Means

Drop Detector not working as expected or cannot be detected

Step-by-Step Troubleshooting Guide

1
Restart the device. Check the Drop detector to Service station cable. Run the 02101 Check Electronics service diagnostic. Replace the Drop Detector. Replace the Service station PCA

Technical Service Diagrams

Reference diagrams for common repair procedures related to this error:

Carriage Belt Replacement

Note: These diagrams are for reference only. Always consult official HP service documentation and follow proper ESD precautions.

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Media Sensor

Optical or mechanical sensors that detect the presence, type, width, and position of print media loaded in the printer.

Error Code

A numeric or alphanumeric code displayed on the printer's front panel or in diagnostic logs that identifies a specific hardware or software malfunction.

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