---
title: "Connected Vehicles & Telematics with MQTT | ConnectMQ"
description: "Connect vehicles to your cloud over MQTT: telematics from the TCU, remote commands with QoS 1 and OTA campaign messages to vehicle groups over cellular links."
url: "https://connectmq.com/use-cases/connected-vehicles/"
language: "en"
---

Use case

# Connected vehicles, from TCU to cloud

The telematics control unit in each vehicle publishes position, CAN signals, battery and diagnostic data to ConnectMQ and receives remote commands on its own topics. Your vehicle backend, mobile app and service tools subscribe — over cellular links that come and go.

[Try it free](https://app.connectmq.com/signup) [See pricing](https://connectmq.com/pricing/)

No card required

Used in

-   [Automotive](https://connectmq.com/industries/automotive/)
-   [Transportation & Logistics](https://connectmq.com/industries/transportation-logistics/)

Example message

PUBLISH vehicles/veh-20417/telemetry

```
{"ts":"2026-10-22T07:42:10Z","lat":52.5201,"lon":13.4049,"speed_kmh":48,"soc":71,"odo_km":38412,"dtc":[]}
```

QoS 1 · TLS 8883 · PUBACK

The problem

## A vehicle is a device on a bad network

Vehicles drive through tunnels, underground car parks and roaming zones. HTTP polling from the TCU wastes data and misses commands, and every new service — remote unlock, pre-conditioning, diagnostics, software campaigns — tends to bring its own connection to the car. Engineering teams end up maintaining several pipelines to the same vehicle.

## How it works

1.  1
    
    ### The TCU publishes telematics
    
    The TCU or an in-vehicle gateway reads CAN and OBD signals and publishes position, speed, state of charge, DTCs and status to the vehicle’s topics in compact JSON or binary payloads.
    
2.  2
    
    ### Your backend subscribes
    
    The vehicle backend, data platform and driver or fleet apps subscribe to what they need — one vehicle, a model line or the whole fleet through wildcards.
    
3.  3
    
    ### Remote commands
    
    The app or backend publishes a command — lock, unlock, climate, locate — with QoS 1. The vehicle acknowledges on a response topic, and a persistent session holds the command while the vehicle is offline.
    
4.  4
    
    ### OTA campaign coordination
    
    Your OTA service publishes a campaign notice with the package URL to a vehicle group. Vehicles download the package from your servers and report download, install and version status over MQTT.
    

ConnectMQ

## What it needs from the broker

### Made for cellular

Small MQTT headers, a configurable keep-alive and persistent sessions keep data use low and let a vehicle catch up on queued messages after a dead zone.

### Commands that arrive once and on time

QoS 1 for commands and campaign messages; MQTT 5 message expiry and response topics help make sure a stale unlock is never executed hours later.

### An identity per vehicle

Each vehicle gets its own credentials and ACL, so a TCU can only publish to and receive from its own topics.

### Online status

Last Will and a retained status topic tell the backend at once when a vehicle goes offline and when it is back.

## What you get

-   One connection per vehicle for telematics, commands and campaigns
-   Remote commands that still reach the vehicle after a dead zone
-   Live campaign progress per vehicle and per software version
-   Less cellular data than polling-based telematics

Example topics

```
vehicles/veh-20417/telemetry
vehicles/veh-20417/commands
vehicles/veh-20417/commands/response
vehicles/veh-20417/status                (retained)
ota/campaigns/tcu-fw-4-2/announce        (retained)
```

## Industries that run this use case

 [![](https://connectmq.com/images/industries/hero/automotive.webp) Automotive](https://connectmq.com/industries/automotive/) [![](https://connectmq.com/images/industries/hero/transportation-logistics.webp) Transportation & Logistics](https://connectmq.com/industries/transportation-logistics/)

## Related solutions

[

### Fleet Telematics

Vehicle tracking, telematics and cold chain

Learn more](https://connectmq.com/fleet-logistics/)[

### Connected Products & Smart Hardware

Smart devices you ship to your own customers

Learn more](https://connectmq.com/connected-products/)

## Frequently asked questions

Is MQTT used for connected cars?

Yes. MQTT is widely used between telematics units and vehicle clouds because it is lightweight, keeps one long-lived connection open and copes well with cellular coverage that comes and goes. Most cloud IoT platforms and many telematics stacks support it.

Can I send OTA updates over MQTT?

MQTT is well suited to coordinating a campaign: notifying a vehicle group, collecting download and install progress and confirming the new version. The update package itself is normally downloaded over HTTPS from your OTA service or CDN — ConnectMQ does not host or sign packages.

How do I secure remote commands to a vehicle over MQTT?

Use TLS, unique credentials per vehicle and ACLs, so only your backend may publish to a vehicle’s command topic and each vehicle reads only its own. Add a command ID, an expiry and an acknowledgement on a response topic, and validate every command in the vehicle before acting on it.

## Build it on ConnectMQ

Start on the Free plan — no card required — connect your first devices today and upgrade when you go live.

[Get started](https://app.connectmq.com/signup) [See pricing](https://connectmq.com/pricing/)

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## Articles

[All articles](https://connectmq.com/blog/)

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### [How to Choose an IoT MQTT Broker: 12 Criteria and the Questions to Ask Your Vendor](https://connectmq.com/blog/how-to-choose-an-iot-mqtt-broker/)

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### [MQTT Security Best Practices: A 12-Point Checklist for IoT Teams](https://connectmq.com/blog/mqtt-security-best-practices/)

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