What does this mean?
Your camper is equipped with a safety feature that prevents the heater from starting if a nearby window is open.
This is to ensure safe ventilation.
In some cases, the sensor may not correctly detect that the window is closed.
Models this applies to
Volkswagen Grand California
Step-by-step solution
1. Check the window
Locate the window near the heater (usually above or next to the wall vent)
Make sure it is fully closed
Ensure the window is properly locked
2. Locate the window sensor
Find the small black sensor inside the camper
Typically located near the inside table, opposite the Truma heater
3. Activate the sensor
Close the window firmly so it presses against the sensor
Make sure the sensor is being triggered
4. Temporary fix (if needed)
If the error remains:
Place a small, firm object (e.g. folded paper) over the sensor
This applies pressure and helps the sensor detect the window as closed
5. Check the control panel
Look at the Truma CP Plus panel
If the error code disappears, the issue is resolved
Still not working?
If the error remains:
Contact us via our website (Joey)
Include a photo of the panel and error code
Good to know
This is a common safety feature, not a fault
The heater will not start if the window sensor is not triggered
Always ensure proper ventilation when using the heater