HP DesignJet Z2100

Designjet Z Series — Service Manual 2-25
System Error Codes - Full Descriptions
problem.  Page 3-38.
 Replace the Left or Right Ink Supply Stations, depending on the results of
the diagnostic test 
Page 6-143 and Page 6-147.
 If the problems persist after replacing the appropriate ink supply station
(right or left), replace the Main PCA if you have problems with the left
side. Replace the Printmech PCA if you have problems with the right side.
System Error: 94:YZ
Problem
Description:
Color calibration Error.
Corrective Action: Try the following:
 Perform the Color Sensor ESP (spectrophotometer) calibration. You must
use glossy paper for this calibration.
 If the System Error continues, replace the Color Sensor ESP
(spectrophotometer) 
Page 6-122.
 If the System Error continues, replace the Carriage PCA  Page 6-138.
 If the System Error continues, replace the Formatter  Page 6-159.