diff --git a/LDDsimulation/LDDsimulation.py b/LDDsimulation/LDDsimulation.py
index 1c678b0722b614ee8a5b44c807c4f505fb7f1cad..c33fcf0d2e2a4b0e51565d4022b14b6b78a97df2 100644
--- a/LDDsimulation/LDDsimulation.py
+++ b/LDDsimulation/LDDsimulation.py
@@ -580,6 +580,7 @@ class LDDsimulation(object):
                     subdomain_index=sd_index,
                     errors=subsequent_iter_error
                     )
+
             if analyse_condition and self.write2file['condition_numbers']:
                 # save the calculated condition numbers of the assembled
                 # matrices a separate file for monitoring
diff --git a/LDDsimulation/domainPatch.py b/LDDsimulation/domainPatch.py
index 84dc252e50ca83f6087cecf064aff3a69387a10c..81121e0db045ef95d9b12919ebe1829bd248a8ef 100644
--- a/LDDsimulation/domainPatch.py
+++ b/LDDsimulation/domainPatch.py
@@ -1238,12 +1238,28 @@ class DomainPatch(df.SubDomain):
                             "pressure(t="+"{}".format(t)+")_"+"{}".format(phase)
                             )
                 file.write(self.pressure[phase], i)
+
+                if phase == "wetting":
+                    data_set_name="subs_err_w"
+                    data_set_name_abs="subs_err_abs_diff_w"
+                else:
+                    data_set_name="subs_err_nw"
+                    data_set_name_abs="subs_err_abs_diff_nw"
+
                 # create function to copy the subsequent errors to
-                error = df.Function(self.function_space["pressure"][phase])
-                error.assign(self.pressure[phase] - self.pressure_prev_iter[phase])
-                error.rename("pi_"+"{}".format(phase)+"-pim1_"+"{}".format(phase), #
-                            "pressure(t="+"{}".format(t)+")_"+"{}".format(phase)
-                            )
-                file.write(error, i)
+                subsequent_diff = df.Function(self.function_space["pressure"][phase])
+                subsequent_diff.assign(self.pressure[phase] - self.pressure_prev_iter[phase])
+                # subsequent_diff.rename("pi_"+"{}".format(phase)+"-pim1_"+"{}".format(phase), #
+                #             "pressure(t="+"{}".format(t)+")_"+"{}".format(phase)
+                #             )
+                subsequent_diff.rename(data_set_name)
+                file.write(subsequent_diff, i)
+                
+                abs_subsequent_diff = df.Function(subdomain.function_space["pressure"][phase])
+                np_subsequent_diff = subsequent_diff.vector()[:]
+                abs_diff_tmp = np.fabs(np_subsequent_diff)
+                abs_subsequent_diff.vector()[:] = abs_diff_tmp
+                abs_subsequent_diff.rename(data_set_name_abs)
+                file.write(abs_subsequent_diff, i)
 
 # END OF CLASS DomainPatch