diff --git a/test/parallel/test-error-codes-impl-doc.js b/test/parallel/test-error-codes-impl-doc.js
new file mode 100644
index 00000000000000..8ec0fb73fb7c78
--- /dev/null
+++ b/test/parallel/test-error-codes-impl-doc.js
@@ -0,0 +1,158 @@
+'use strict';
+
+// Flags: --expose-internals
+
+// Note: this script reads Node.js sources and docs, and expects to be run on
+// the very same Node.js version as the source and doc tree is.
+
+require('../common');
+const assert = require('assert');
+const errors = require('internal/errors').codes;
+const fs = require('fs');
+const path = require('path');
+const natives = process.binding('natives');
+
+// --report prints only the list of failed checks and does not assert
+const report = process.argv[2] === '--report';
+const results = [];
+function check(ok, type, name, reason) {
+  const label = `${type}: ${name} - ${reason}`;
+  if (report) {
+    if (!ok) results.push(label);
+  } else {
+    assert.ok(ok, label);
+  }
+}
+
+const set = {
+  all: new Set(),
+  js: new Set(), // Error codes found in natives.
+  doc: new Set(), // Error codes mentioned in `doc/api/*.md`.
+  cpp: new Set(), // Error codes found in `src/node_errors.h`.
+  noargs: new Set(), // Subset of `js` which is constructed without arguments.
+  // `set.manual` contains errors manually created from js and not defined in
+  // internals/errors. That is not scanned now, update this list if required.
+  manual: new Set(['ERR_HTTP2_ERROR', 'ERR_UNKNOWN_BUILTIN_MODULE']),
+  // `set.examples` contains errors mentioned in documentation purely for
+  // demonstration purposes. These errors are not required to be present.
+  examples: new Set(['ERR_ERROR_1'])
+};
+
+const root = path.join(__dirname, '..', '..');
+
+// File containing error definitions
+const jsdata = natives['internal/errors'];
+// File containing error documentation
+let docdata = fs.readFileSync(path.join(root, 'doc/api/errors.md'), 'utf-8')
+docdata = docdata.replace(/## Legacy [\s\S]*/, '');
+// File containing cpp-side errors
+const cppdata = fs.readFileSync(path.join(root, 'src/node_errors.h'), 'utf-8');
+// Directory containing documentation
+const docdir = path.join(root, 'doc/api/');
+
+function addSource(source, type) {
+  // eslint-disable-next-line node-core/no-unescaped-regexp-dot
+  const re = /(.)?(ERR_[A-Z0-9_]+)(..)?/g;
+  let match;
+  while (match = re.exec(source)) {
+    if (match[1] === '_') continue; // does not start with ERR_
+    const name = match[2];
+    if (type === 'doc' && set.examples.has(name)) continue; // is an example
+    set.all.add(name);
+    set[type].add(name);
+    if (type === 'js' && match[3] === '()') {
+      // Is directly called without arguments from js, we will try that
+      set.noargs.add(name);
+    }
+  }
+}
+
+// Add all errors from JS natives
+for (const file of Object.keys(natives)) addSource(natives[file], 'js');
+// Add all errors from src/node_errors.h
+addSource(cppdata, 'cpp');
+// Add all errors from doc/api/*.md files
+for (const file of fs.readdirSync(docdir)) {
+  if (!file.endsWith('.md')) continue;
+  let data = fs.readFileSync(path.join(docdir, file), 'utf-8');
+  if (file === 'errors.md') data = data.replace(/## Legacy [\s\S]*/, '');
+  addSource(data, 'doc');
+}
+
+// Check that we have all js errors
+for (const name of set.js) {
+  if (set.manual.has(name)) continue;
+  const defined = jsdata.includes(`E('${name}',`);
+  check(defined, 'js', name, 'missing JS implementation (source)');
+  if (defined) {
+    check(errors[name], 'js', name, 'missing JS implementation (runtime)');
+  }
+}
+
+// Check that we can initialize errors called without args
+for (const name of set.noargs) {
+  if (!errors[name]) continue; // Already catched that above
+  let ok = true;
+  try {
+    new errors[name]();
+  } catch (e) {
+    ok = false;
+  }
+  check(ok, 'init', name, 'failed init without args, but is called with "()"');
+}
+
+// Check that we have implementation for all errors mentioned in docs.
+// C++ does not need that, and JS is already checked above.
+for (const name of set.doc) {
+  const ok = set.manual.has(name) ||
+             name.startsWith('ERR_NAPI_') || // napi errors are created directly
+             jsdata.includes(`E('${name}',`) ||
+             cppdata.includes(`V(${name}, `);
+  const reason = docdata.includes(`### ${name}\n`) ?
+    'documented' : 'mentioned in doc/api/';
+  check(ok, 'impl', name, `missing implementation, ${reason}`);
+}
+
+// Check that we have documentation for all errors
+for (const name of set.all) {
+  const ok = docdata.includes(`### ${name}\n`);
+  check(ok, 'doc', name, 'missing documentation');
+  // Check that documentation references are correctly formatted
+  if (ok) {
+    const anchor = docdata.includes(`\n\n<a id="${name}"></a>\n### ${name}\n`);
+    check(anchor, 'doc', name, 'missing anchor or not properly formatted');
+  }
+}
+
+// Check that documentation is sorted, formatted, and does not contain dupes
+{
+  const compare = (a, b) => {
+    // HTTP2_ should come after HTTP_
+    if (a.startsWith('ERR_HTTP_') && b.startsWith('ERR_HTTP2_')) return -1;
+    if (a.startsWith('ERR_HTTP2_') && b.startsWith('ERR_HTTP_')) return 1;
+    if (a < b) return -1;
+    if (a > b) return 1;
+    return 0;
+  };
+  const re = /\n### (ERR_[A-Z0-9_]+)\n/g;
+  let match;
+  let last;
+  const documented = new Set();
+  while (match = re.exec(docdata)) {
+    const name = match[1];
+    if (documented.has(name)) {
+      check(false, 'doc', name, 'duplicate documentation entry');
+    } else {
+      const sorted = !last || compare(name, last) === 1;
+      check(sorted, 'doc', name, 'is out of order');
+      documented.add(name);
+    }
+    last = name;
+  }
+}
+
+if (report) {
+  console.log('Report mode');
+  console.log(results.join('\n'));
+  console.log(`There were ${results.length} problems found`);
+}