diff --git a/html/assets/js/selftest.js b/html/assets/js/selftest.js
index 1080104..fe96879 100644
--- a/html/assets/js/selftest.js
+++ b/html/assets/js/selftest.js
@@ -320,10 +320,10 @@ async function selfTestSequence() {
 
       try {
         if (sensor.type === 'npm') {
-          // NPM sensor test
+          // NPM sensor test (uses get_data_modbus_v3.py --dry-run)
           const npmResult = await new Promise((resolve, reject) => {
             $.ajax({
-              url: 'launcher.php?type=npm&port=' + sensor.port,
+              url: 'launcher.php?type=npm',
               dataType: 'json',
               method: 'GET',
               timeout: 15000,
@@ -333,17 +333,30 @@ async function selfTestSequence() {
           });
 
           selfTestReport.rawResponses['NPM Sensor'] = JSON.stringify(npmResult, null, 2);
-          addSelfTestLog(`NPM response: PM1=${npmResult.PM1}, PM2.5=${npmResult.PM25}, PM10=${npmResult.PM10}`);
+          addSelfTestLog(`NPM response: PM1=${npmResult.PM1}, PM2.5=${npmResult.PM25}, PM10=${npmResult.PM10}, status=${npmResult.npm_status_hex}`);
 
-          // Check for errors
-          const npmErrors = ['notReady', 'fanError', 'laserError', 'heatError', 't_rhError', 'memoryError', 'degradedState'];
-          const activeErrors = npmErrors.filter(e => npmResult[e] === 1);
+          // Decode npm_status flags
+          const status = npmResult.npm_status || 0;
+          const statusFlags = {
+            0x01: "Sleep mode",
+            0x02: "Degraded mode",
+            0x04: "Not ready",
+            0x08: "Heater error",
+            0x10: "THP sensor error",
+            0x20: "Fan error",
+            0x40: "Memory error",
+            0x80: "Laser error"
+          };
+          const activeErrors = [];
+          Object.entries(statusFlags).forEach(([mask, label]) => {
+            if (status & mask) activeErrors.push(label);
+          });
 
           if (activeErrors.length > 0) {
-            updateTestStatus(sensor.id, 'Warning', `Errors: ${activeErrors.join(', ')}`, 'bg-warning');
+            updateTestStatus(sensor.id, 'Warning', `Status ${npmResult.npm_status_hex}: ${activeErrors.join(', ')}`, 'bg-warning');
             testsFailed++;
           } else if (npmResult.PM1 !== undefined && npmResult.PM25 !== undefined && npmResult.PM10 !== undefined) {
-            updateTestStatus(sensor.id, 'Passed', `PM1: ${npmResult.PM1} | PM2.5: ${npmResult.PM25} | PM10: ${npmResult.PM10} ug/m3`, 'bg-success');
+            updateTestStatus(sensor.id, 'Passed', `PM1: ${npmResult.PM1} | PM2.5: ${npmResult.PM25} | PM10: ${npmResult.PM10} µg/m³`, 'bg-success');
             testsPassed++;
           } else {
             updateTestStatus(sensor.id, 'Warning', 'Incomplete data received', 'bg-warning');