diff --git a/plexpl3.dtx b/plexpl3.dtx
index 5ccb2fc..a426d34 100644
--- a/plexpl3.dtx
+++ b/plexpl3.dtx
@@ -606,6 +606,88 @@
   { \__regex_replacement_put:n {#2} }
 %    \end{macrocode}
 %
+% \subsection{コードポイント関数の修正}
+%
+% Fix for codepoint functions in \file{l3text}.
+%    \begin{macrocode}
+%<@@=text>
+%    \end{macrocode}
+%    \begin{macrocode}
+\cs_gset:Npn \@@_codepoint_process:nN #1#2
+  {
+%    \end{macrocode}
+% Check if the given character token is a jachar.
+% One jachar token is one codepoint.
+%    \begin{macrocode}
+    \token_if_jachar:NTF #2
+      { \use:n }
+      {
+        \int_compare:nNnTF { `#2 } > { "80 }
+          {
+            \int_compare:nNnTF { `#2 } < { "E0 }
+              { \@@_codepoint_process:nNN }
+              {
+                  \int_compare:nNnTF { `#2 } < { "F0 }
+                    { \@@_codepoint_process:nNNN }
+                    { \@@_codepoint_process:nNNNN }
+              }
+          }
+      }
+      { \use:n }
+        {#1} #2
+  }
+%    \end{macrocode}
+%    \begin{macrocode}
+\cs_gset:Npn \@@_codepoint_compare:N #1
+  {
+%    \end{macrocode}
+% Check if the given character token is a jachar.
+%    \begin{macrocode}
+    \token_if_jachar:NTF #1
+      { \@@_codepoint_compare_jachar:N }
+      {
+        \if_int_compare:w `#1 > "80 \exp_stop_f:
+          \if_int_compare:w `#1 < "E0 \exp_stop_f:
+            \exp_after:wN \exp_after:wN \exp_after:wN
+              \@@_codepoint_compare:NN
+          \else:
+            \if_int_compare:w `#1 < "F0 \exp_stop_f:
+              \exp_after:wN \exp_after:wN \exp_after:wN
+              \exp_after:wN \exp_after:wN \exp_after:wN
+              \exp_after:wN \@@_codepoint_compare:NNN
+            \else:
+              \exp_after:wN \exp_after:wN \exp_after:wN
+              \exp_after:wN \exp_after:wN \exp_after:wN
+              \exp_after:wN \@@_codepoint_compare:NNNN
+            \fi:
+          \fi:
+        \else:
+          \exp_after:wN \@@_codepoint_compare_aux:N
+        \fi:
+      }
+      #1
+  }
+%    \end{macrocode}
+%    \begin{macrocode}
+\int_compare:nNnTF { \tex_jis:D "2121 } = { "3000 }
+  {
+%    \end{macrocode}
+% up\TeX{} with unicode.
+%    \begin{macrocode}
+    \cs_new:Npn \@@_codepoint_compare_jachar:N #1 { `#1 }
+  }
+  {
+%    \end{macrocode}
+% p\TeX{} or up\TeX{} with euc/sjis.
+%    \begin{macrocode}
+    \cs_new:Npn \@@_codepoint_compare_jachar:N #1
+      { \tex_toucs:D `#1 \exp_stop_f: }
+  }
+%    \end{macrocode}
+%    \begin{macrocode}
+%<@@=>
+%    \end{macrocode}
+%
 % 以上です。
 %    \begin{macrocode}
 %</code>
diff --git a/testfiles/pl3text002.lvt b/testfiles/pl3text002.lvt
new file mode 100644
index 0000000..d53fc1b
--- /dev/null
+++ b/testfiles/pl3text002.lvt
@@ -0,0 +1,38 @@
+%
+% Copyright (c) 2022 Japanese TeX Development Community
+%
+\epTeXinputencoding utf8
+
+\input{regression-test}
+\documentclass{minimal}
+\RequirePackage[enable-debug]{expl3}
+\ExplSyntaxOn
+\debug_on:n { check-declarations , deprecation , log-functions }
+\ExplSyntaxOff
+
+\RequirePackage{plexpl3}
+
+\begin{document}
+
+\START
+\ExplSyntaxOn
+
+\cs_new:Npn \test_map:n #1 { [#1] }
+
+\TESTEXP { text_map_function }
+  {
+    \text_map_function:nN
+      { ABC~äëïöü~αβγ~あいうえお~か゚き゚く゚け゚こ゚~葛󠄀城市~葛󠄁飾区~☀☁☂☃~⛄👨‍👩‍👧‍👦💔 }
+      \test_map:n
+  }
+
+\TEST { text_map_inline }
+  {
+    \text_map_inline:nn
+      { ABC~äëïöü~αβγ~あいうえお~か゚き゚く゚け゚こ゚~葛󠄀城市~葛󠄁飾区~☀☁☂☃~⛄👨‍👩‍👧‍👦💔 }
+      {
+        \TYPE { [#1] }
+      }
+  }
+
+\END
diff --git a/testfiles/pl3text002.tlg b/testfiles/pl3text002.tlg
new file mode 100644
index 0000000..3ccca6d
--- /dev/null
+++ b/testfiles/pl3text002.tlg
@@ -0,0 +1,60 @@
+This is a generated file for the l3build validation system.
+Don't change this file in any respect.
+Defining \test_map:n on line ...
+============================================================
+TEST 1: text_map_function
+============================================================
+[A][B][C][ ][^^c3^^a4][^^c3^^ab][^^c3^^af][^^c3^^b6][^^c3^^bc][ ][α][β][γ][ ][あ][い][う][え][お][ ][か^^e3^^82^^9a][き^^e3^^82^^9a][く^^e3^^82^^9a][け^^e3
+^^82^^9a][こ^^e3^^82^^9a][ ][葛^^f3^^a0^^84^^80][城][市][ ][葛^^f3^^a0^^84^^81]
+[飾][区][ ][^^e2^^98^^80][^^e2^^98^^81][^^e2^^98^^82][^^e2^^98^^83][ ][^^e2^^9b
+^^84][^^f0^^9f^^91^^a8^^e2^^80^^8d][^^f0^^9f^^91^^a9^^e2^^80^^8d][^^f0^^9f^^91^^a7^^e2^^80^^8d][^^f0^^9f^^91^^a6][^^f0^^9f^^92^^94]
+============================================================
+============================================================
+TEST 2: text_map_inline
+============================================================
+[A]
+[B]
+[C]
+[ ]
+[^^c3^^a4]
+[^^c3^^ab]
+[^^c3^^af]
+[^^c3^^b6]
+[^^c3^^bc]
+[ ]
+[α]
+[β]
+[γ]
+[ ]
+[あ]
+[い]
+[う]
+[え]
+[お]
+[ ]
+[か^^e3^^82^^9a]
+[き^^e3^^82^^9a]
+[く^^e3^^82^^9a]
+[け^^e3^^82^^9a]
+[こ^^e3^^82^^9a]
+[ ]
+[葛^^f3^^a0^^84^^80]
+[城]
+[市]
+[ ]
+[葛^^f3^^a0^^84^^81]
+[飾]
+[区]
+[ ]
+[^^e2^^98^^80]
+[^^e2^^98^^81]
+[^^e2^^98^^82]
+[^^e2^^98^^83]
+[ ]
+[^^e2^^9b^^84]
+[^^f0^^9f^^91^^a8^^e2^^80^^8d]
+[^^f0^^9f^^91^^a9^^e2^^80^^8d]
+[^^f0^^9f^^91^^a7^^e2^^80^^8d]
+[^^f0^^9f^^91^^a6]
+[^^f0^^9f^^92^^94]
+============================================================
diff --git a/testfiles/pl3text002.uptex.tlg b/testfiles/pl3text002.uptex.tlg
new file mode 100644
index 0000000..0f6e253
--- /dev/null
+++ b/testfiles/pl3text002.uptex.tlg
@@ -0,0 +1,59 @@
+This is a generated file for the l3build validation system.
+Don't change this file in any respect.
+Defining \test_map:n on line ...
+============================================================
+TEST 1: text_map_function
+============================================================
+[A][B][C][ ][^^c3^^a4][^^c3^^ab][^^c3^^af][^^c3^^b6][^^c3^^bc][ ][α][β][γ][ ][あ][い][う][え][お][ ][か゚][き゚][く゚][け゚][こ゚][ ][葛
+󠄀][城][市][ ][葛󠄁][飾][区][ ][☀][☁][☂][☃][ ][⛄][👨‍][
+👩‍][👧‍][👦][💔]
+============================================================
+============================================================
+TEST 2: text_map_inline
+============================================================
+[A]
+[B]
+[C]
+[ ]
+[^^c3^^a4]
+[^^c3^^ab]
+[^^c3^^af]
+[^^c3^^b6]
+[^^c3^^bc]
+[ ]
+[α]
+[β]
+[γ]
+[ ]
+[あ]
+[い]
+[う]
+[え]
+[お]
+[ ]
+[か゚]
+[き゚]
+[く゚]
+[け゚]
+[こ゚]
+[ ]
+[葛󠄀]
+[城]
+[市]
+[ ]
+[葛󠄁]
+[飾]
+[区]
+[ ]
+[☀]
+[☁]
+[☂]
+[☃]
+[ ]
+[⛄]
+[👨‍]
+[👩‍]
+[👧‍]
+[👦]
+[💔]
+============================================================