Webasto Airtop 2000 st problems

[Sam j]

Hi All,

I have a puzzling issue with my AT2000 st.

The crux of the problem is that the fuel pump will not run and throws the 1 flash failure to start code.

If I tap 12v to the pump directly it will work.

If I connect the switching contacts of a relay to the fuel pump wiring, the relay clicks.

If I connect a 12v battery to the switched contacts of the relay and then to the pump it runs and the heater works.

I have replaced the pump ecu with a second hand unit - still not working.

I have replaced the rest of the heater with a second hand unit - still not working.

I have wired the heater directly to a battery with fresh cables - still not working

I am very much out of ideas at this point. The only items that I have not changed are the rheostat, the pump and the wiring loom.

Has anyone else had a similar experience or can offer some direction?

Best regards

Sam

 

[Stemar]

I can't help with your particular issue, but do your sums before spending much on fixing it. A new Chinaspacher may well cost less than the bits for a Webasto.

 

[Sam j]

Yes that has crossed my mind. I found a cheap secondhand until that I have used for the spares mentioned above but I would need to buy a controller and pump to complete the set which will cost ££

 

[Sam j]

It turns out it was the fuel pump. Even though I could pulse it manually with a 12v battery the heater could not run it. It had 0.7ohms across the pump terminals, this should be around 5 apparently.

I hope this thread will help someone in the future