Error 17 on Autoterm Air / Planar auxiliary heaters
What does error 17 mean
Error 17 (or 7 flashes on the PU-5 control panel) means there is a problem with the fuel pump - it is either electrically undetectable, or it draws much more current than it should.
Causes
Error 17 during initial installation
Error 17 often appears during the initial installation of the heater; in almost all cases the contacts of the plug connections were not made properly. The two plugs are fitted with individual wire seals so that they are truly sealed and protected from moisture and dirt at the intended mounting location under the vehicle. For this reason they are somewhat hard to push in. Make sure they really latch in properly. Both must sit at the same height at the end of the plug housing - if one sits a little further back than the other, you have already found the error.
By the way, the installation instructions also describe which way round they must be plugged in.
Error 17 when operating an installed heater
Of course, things look different if the heater previously ran without problems.
It is certainly possible that the fuel pump cable was chewed through by a marten, or that someone stole the pump. However, that is rather unlikely. On the other hand, two things are often overlooked when handling the heater and repeatedly lead to this error:
The heater is not used for a longer period, e.g. over the summer months.
The problem: diesel turns gummy after some time, meaning that if the fuel sits unmoved in the system for a long time, it glues the pump piston. When it tries to move, an extremely high current is drawn, the heater notices that something is wrong and switches off.
As a precaution, the heater should be started once every 4 weeks.
Heater won't start after filling up with winter diesel
Winter diesel is delivered to our filling stations at the beginning of October. It is more resistant to low temperatures and doesn't wax up as quickly in the cold. It happens again and again that the first winter diesel ends up in the vehicle's tank in October, but the first trip is not due until Christmas. If the heater has not been started by then and the winter diesel pumped into the lines, the low temperatures will have turned the summer diesel still in there into a wobbly mass by the time you need the heater.
The pump does its best to deliver this viscous stuff, but draws too much current in the process and the heater switches off.
Feel free to also watch our video on error 13, as very similar causes can be behind it.
So when winter diesel has been filled, the heater should also be started right away to distribute the diesel in the lines and the pump.
Water in the tank.
Water in the tank and lines of the fuel system can of course also freeze and cause damage. Water can accumulate there through normal so-called "tank breathing", i.e. the change in air volume with temperature changes. Through the vent, some fresh air always gets into the tank, and its moisture condenses on the cold tank walls. Tank breathing with condensation of air humidity causes problems primarily in vehicles that stand for long periods.
On long-distance trips to countries with poor fuel quality, the problem can be correspondingly more severe due to diluted or contaminated fuel.
Water in the tank leads not only to freezing at low temperatures but also to corrosion. Small rust particles that form in the tank (or contamination from poor fuel quality) can cause the pump to jam and also produce error 17.
You should therefore install at least a particle filter upstream of the heater's pump. That is why such a filter is included directly in our camper kits, but you can also order it as a single item or spare part if necessary.
We also equip the kits with the "Extra Quiet" pump as standard, which allows you to clean a small internal strainer, so the pump doesn't have to be thrown away if particles should get into it after all. The Extra Quiet pump can also be ordered separately as a replacement for the older model.
If possible, and especially if you are planning long-distance trips, please also consider installing a water separator in the fuel system.
Fuel pump defective
A fuel pump that is defective on its own cannot be categorically ruled out either, but it really happens extremely rarely. In most cases the defect then occurs "out of the box", i.e. right on delivery.
Fuel pumps that only break after a longer period of operation are usually damaged by dirt particles from the vehicle tank. So please really make sure the small filter is installed, to spare yourself this trouble.
Conclusion
During initial installation it is very often a matter of contacts that are not connected properly. If the pump fails during operation, cables may have been damaged, or the electrical connection is there but the pump cannot move properly due to gumming, waxing or dirt particles, which is why you should make sure to run the heater regularly and install a filter.
Problems fixing the error?
Of course, by remote diagnosis we can only help to a limited extent with troubleshooting on a specific vehicle. With the tips in this article, error 17 can usually be fixed yourself, but if you would like professional help, you are of course welcome to contact one of our installation partners, who can look for the solution directly on the vehicle. You can find the list for getting in touch here.All important error codes on Autoterm Air / Planar auxiliary heaters - overview
(Flash codes = PU-5 control panel)