Hi folks,
Sorry to butt in as I don't have a caravan but I found your post on google, and after reading it I joined up to share my experience as I think it may it may help you as my vehicle had the same symptoms.(and I will feel better for having my whinge about Mazda Australia)
I have a 2012 BT50 3.2 4x4 Six Speed Manual which has been in the Mazda Workshop for the past 3 weeks plus and still is, with the Limp Home problem you describe. It has done about 95,000kms, I am an Industrial Electrician and I carry a minimum of 400kg of tools and gear on the back since I the day I brought it home.
At about the 60,000 mark my car went in to limp mode for the first time and then probably did it once a week for about 6 weeks until I noticed the dash warning light flash briefly in the dark. I took it to my Mechanic (Not a Mazda Dealer) and he could not find a fault code. We suspected a loose earth as it seemed to happen when I went through roundabouts or over rough terrain. He went over the car, couldn't find anything but the problem disappeared for about 3 months, then came back gradually. Once a week at first, every second day then it became a daily occurrence over a couple of months.
I took it to Mazda and the Mechanic suspected the "Fuel Temperature Sensor", cleared the fault log and advised me to book it in with them. The problem then promptly disappeared again for a few weeks. So I didn't go back and I drove the car without any issues for a while..
I only keep my work cars for 3 years and at about 80,000 it began happening again and by now I was thinking of replacing it anyway.
I just put up with and flicked the ignition off and back on while driving.
Eventually, it started doing it 3,4,5 times a day and more if I was towing, particularly uphill. I took it to a Mazda dealer and they replaced the Fuel filter that was only 10,000kms old, told me it was still doing it and we started the fight to have it fixed before the warranty expired. After getting back this time it was almost undriveable, 30 times in a 200km day was not unusual, then maybe nothing for the next 200kms.
Mazda agreed to fix it under Warranty and they have had it for 26 days and still counting! The Service Manager just fed me BS but I got to speak to the actual Mechanic who is working on the car when I went to retrieve all of tool boxes and gear. He showed me the Injector Pump and told it this is not necessarily common, but it is not unheard of either.
The Injector Pump has 3 pistons running on a Cam, one piston on my car had been sticking and had left score marks on the Cam. This causes the fuel to get stuck in the chamber and overheat which then sets off the Fuel Temp Sensor and sends the car into limp mode. Sweet, change the Injector Pump and she will be good as new I thought. Wrong!!
My trouble is Mazda has no Injector Pumps in Australia and even though the Service Manager told me Ford have plenty, Ford charge Madza more and they wont buy them off Ford on principle. But Mazda Australia were happy enough to Hire me a Ute form Hertz for 14 days!!
Surely the cost of Ute hire outweighs any extra they pay! I rely on my Car and there has been no real effort to hurry the process up on Mazda's behalf. The Hire ute was useless as I couldn't secure my Tools so I bought another car anyway.
Moral of the story is if you rely on having your vehicle to earn a living don't buy a Mazda, I've bought a Colorado now and hopefully I have more luck with it.
By the way - If I ever get the BT50 back, it is up for urgent sale as I am now paying off 2 work vehicles, if you are in the Market for a used BT50 with a new Injector Pump let me know..