docs(mqtt): add service mode topic to MQTT integration documentation

Author: JakobLichterfeld

CHANGELOG.md

@@ -34,6 +34,7 @@
 - docs: update security policy to emphasize network-level protection ([27172cba](https://github.com/teslamate-org/teslamate/commit/27172cba54782f9a8eb7fdd9ea3a481dfd9d8f2b) - @JakobLichterfeld)
 - docs: fix typo in DATABASE_SSL_SNI description (#5346 - @dashitongzhi)
 - docs: update upgrading instructions to emphasize backup before updating more clearly (#5453 - @JakobLichterfeld)
+- docs(mqtt): add service mode topic to MQTT integration documentation (#5472 - @JakobLichterfeld)
 
 ## [4.0.1] - 2026-06-14
 

website/docs/integrations/mqtt.md

@@ -86,6 +86,7 @@ Vehicle data will be published to the following topics:
 | `teslamate/cars/$car_id/active_route_longitude`        | 29.744801                                                                                   | DEPRECATED: Navigation destination longitude (or "nil")                               |
 | `teslamate/cars/$car_id/active_route`                  | _See below_                                                                                 | Navigation details (json blob)                                                        |
 | `teslamate/cars/$car_id/center_display_state`          | 0                                                                                           | Center Display State                                                                  |
+| `teslamate/cars/$car_id/service_mode`                  | false                                                                                       | Whether Service Mode is active or not                                                 |
 
 :::note
 `$car_id` usually starts at 1