Truma Combi Failure! Help!

Hi All,

My Truma combi 4e has started throwing a E603H error code which appears, from a bit of research, to be an overheating error. I have no idea how this has happened as I can’t recall a scenario that may have caused it but hey, it’s happened.

videos on youtube such as one title " Truma E632H Fault - Hard Reset" have him pushing a ‘hard reset’ button. But on my boiler I cannot fit a finger in the hole as on the video and pushing a screw driver or similar into the little hole i have doesn’t seem to find a button to push. just a big red circle that doesn’t move.

I am currently in Mexico and travelling down to South America where I really need the heat so Truma’s “contact a local engineer” is useless.

Any help, advice, thoughts, experience would be greatly appreciated.



I’ve got the exact same problem and tried so many thing, i don’t have any more Idea.
Did you ever find a solution ? Do someone know what thé problem is ?
Please let me know i’m in Scotland

Hey, I’m really sorry to hear that. It’s an absolute nightmare and unfortunately my ultimate solution was to have my parents bring a diesel heater to Mexico in a suitcase and lug round the 15kg waste of space truma for the next 12 months…. Rant over.

In terms of advice though; from speaking mainly to local technicians not truma I found out the pcb will completely lock and cannot be unlocked unless you have the £700 Trade only diagnostic box to plug in and reset.

My issue I think was that one duct had popped off so the hot air was recirculating in the cupboard and probably tripped a sensor inside. There’s a YouTube video I can’t find right now where someone located the sensor.

I stripped the truma down and tried to bypass sensors but the only option I had to get it fixed on the road was to get a replacement pcb and gamble that any error wasn’t permanent so it wouldn’t lock again, too much of a gamble in my eyes hence the diesel heater solution.

Sadly they’ve built something so complicated it can’t be fixed… computer says no.

I’ll try and find the YouTube for the explanation though.

I also mentioned the hard reset and a button that wouldn’t budge. I realised this was a trip button so if it didn’t budge it hadn’t tripped.

Sorry I can’t be more help, I’d go on the website and find an independent motorhome technician and give them a call.


This is a classic example of why I follow the KISS (Keep It Stupidly Simple) principle. My heaters/cookers are made from dollar store parts, and only cost $6.00 since their price increase. For an additional $20 you can add a heat powered woodstove fan to have electricity free fan forced heat.

It’s basically a 36 wick multi fuel liquid candle made from a cookie tin. I don’t think I’ve ever lit more than 10-12 at a time, but they are available. The wicks are from a dollar store mop, and the floating wick holder is made from craft foam wrapped in a double layer of aluminum foil to protect the foam from the heat. A cake cooling rack on top completes the setup, and the lid keeps everything nice and neat when not in use.

I use a phillips screwdriver to quickly & easily punch X holes in the wick holder to hold the wicks. My current fuel of choice is cooking oil, but kerosene, diesel, or others should work.

Whether you use these regularly like I do or not, knowing how to make them quickly, cheaply, & easily can be a lifesaver when needed.

Ventilation and a carbon monoxide detector are highly recommended.


"Life can be as simple or as complicated as you make it.
Simple is cheaper and more reliable."
~ Off Grid