Subaru IMPREZA 2004 Service Manual page 755

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
8 CHECK ANY OTHER DTCs APPEARANCE. Is any other DTC displayed?
EN(H4SOw/oOBD)(diag)-59
Check
Proceed with the
diagnosis corre-
sponding to the
DTC.
ENGINE (DIAGNOSTICS)
Yes No
A temporary poor
contact.