The Truma Combi D 6 and its electrically boosted sister the Combi D 6 E — often simply called "6DE" in camper circles — are the diesel variants of the well-known Truma Combi heater. Instead of drawing fuel from a gas bottle, they take it straight from the vehicle's tank. That is handy: no bottle swaps, no gas supply running low. It is exactly why the diesel Combi is found in many panel vans and comes as standard in the VW Grand California.
What many owners don't realise: the diesel models can be controlled remotely just as fully. CampMatic controls every supported Combi model, including the diesel D6 and D6E — switching on and off, target temperature, hot water and, on the D6E, even the energy mix between diesel and electric. Via app, Telegram and Home Assistant, from anywhere.
Control the Truma Combi diesel: what CampMatic does with the D6/D6E
CampMatic sits between your Truma CP Plus control panel and the Combi and takes over exactly the functions you would otherwise set on the dial — only remotely:
- Switch on and off — start the heater before you reach the vehicle, and turn it off again.
- Target temperature — set the room temperature to the degree.
- Hot water — switch the boiler on or off separately, choose the hot-water level.
- Energy mix (on the D6E) — on the electrically boosted models you choose between diesel, electric or mix. On shore power you heat cheaply with electricity; on the road you burn diesel.
- Fan mode — switch between quiet (Eco) and fast (High).
- Heating schedule / timer — fixed times at which the heater fires up automatically.
The same applies to the pure gas models (Combi 4/4E/6/6E) — there the energy mix is simply gas/electric/mix instead of diesel/electric. Our post on integrating the Truma heater into Home Assistant shows how it works in principle.
Requirement: Truma CP Plus with firmware from C4.00.00
For control to work, your panel has to be a Truma CP Plus with firmware from C4.00.00. You can check this in seconds: on the CP Plus, show the software version via the INIT menu — if it starts with C4, you're all set for full control.
- CP Plus with C4.xx — full control: on/off, temperature, hot water, energy mix, fan, schedule.
- CP Plus with C3.xx — data is readable (temperature, status), but no control is possible.
Important for the diesel crowd: the Truma iNet X control unit is not supported. CampMatic builds on the CP Plus. Likewise, no parallel original iNet Box runs alongside it — CampMatic replaces it and does more.
Installation: plug-and-play in under 10 minutes
Installation is deliberately simple and needs no tools beyond your hands. CampMatic is plugged in over LinBUS between the CP Plus and the Truma Combi — using the existing RJ11/RJ12 connectors. No soldering, no cutting of cables, no intervention in the heater itself.
- Unplug the panel cable at the CP Plus.
- Plug CampMatic in between (LinBUS looped through).
- Connect 12 V power.
- Set up WiFi or 4G — done.
It has been tested, among others, in the VW Grand California 600 and 680, where the Combi D6E is fitted from the factory. But it works in any vehicle with a compatible Truma heater and a CP Plus from C4 — from a self-built panel van to a full integrated. Typically you're finished in under 10 minutes.
Diesel heater in your motorhome via app: the everyday scenarios
Preheat before you arrive
The classic case: you set off after work, the camper is still sitting cold in the garage or at its pitch. Instead of climbing into a chilled interior, you tap "On" in the app on the way, set 21 °C — and the diesel Combi is warm when you arrive. With diesel that's doubly relaxing, because you don't have to worry about the gas supply: as long as there's diesel in the tank, it heats.
Winter camping with no cold surprises
In winter the frost alert is worth its weight in gold. CampMatic sends you a notification by email and Telegram when the inside temperature drops below your threshold — for example in winter storage, when the camper is 150 km away. With the 4G variant that warning even arrives without any WiFi at the location. So you can react before water pipes freeze, rather than discovering the damage afterwards.
Use shore power cleverly (D6E)
When the camper is on shore power, you want to save the pricey diesel burn. On the D6E you switch the app to electric or mix — the heater then uses the 230 V heating elements. Drive on, and one tap puts it back on diesel. This remote switching is exactly what makes the 6DE so flexible.
Integration: app, Telegram and Home Assistant
CampMatic ties the diesel Combi into your digital ecosystem — whether you like it simple or as a tinkerer:
- CampMatic app (PWA) — runs in the browser on any phone, no app-store install needed. Shows status, temperature and controls.
- Telegram bot — control and query the heater by command, plus push notifications (including a frost alert).
- Home Assistant / MQTT — the Combi appears automatically via auto-discovery as a climate entity. Ideal for your own dashboards and automations.
- ioBroker & Node-RED — also connectable over MQTT.
- Alexa — only possible via Home Assistant (not natively). If you use HA, you can also switch the heater by voice through it.
More than just the heater
The Truma WiFi box does more than heat. Gas and battery monitoring is already included in the Truma boxes: with a Mopeka sensor you see the level of an (optional) gas bottle, with BM2 sensors the voltage of your onboard batteries. The sensors themselves aren't in the box, but the device reads them without any extra hardware — all in the same app, right next to the heater.
Conclusion
The diesel Combi D6 and D6E are not special cases but fully supported: on/off, target temperature, hot water and, on the D6E, the diesel/electric energy mix — all remotely. The requirement is a Truma CP Plus with firmware from C4. Installation is plug-and-play in under 10 minutes, tested in the Grand California and suitable for any compatible vehicle. Whether preheating before arrival, frost protection in winter storage or clever switching on shore power — this finally makes the Truma Combi diesel smart.
→ CampMatic Truma WiFi (GC_HW01) — control the Combi D6/D6E from an app, €149
→ CampMatic Truma 4G (GC_HW_GSM01) — the same, with no WiFi at all, €189
Not sure whether your Combi and CP Plus fit? Check the help or drop us a line — we'll verify your firmware version with you.