This is a question that’s been bugging me for ages now - why does the trailer make a double “hissing” when you turn the ignition on?
Abs/ebs test.
Are you sure it’s the trailer. What unit are you in and is it man or auto
nick2008:
Are you sure it’s the trailer. What unit are you in and is it man or auto
We have 2 identical trailers, one hooked to a CF and mine, hooked to the old Scanny. The DAF (auto) combo gives a rapid series of ‘pfft pfft psst pfft tsst’ (you get the picture!) when the ignition is switched on but the old Scanny does nowt
Isn’t it the ABS purging itself
Pimpdaddy:
Abs/ebs test.
This, the tractor unit is doing the automatic abs/ebs test on the trailer. When the test is completed, the abs/ebs dashboard light will go out provided there is no fault, if there is a fault then the fault will be displayed on the dashboard.
Correct harry, the daf does it because there is air in the service brake when parked, but the Scania doesn’t put air down the yellow line when parked. If you listen carefully when you turn the ignition on the Scania you won’t hear the double blow down but you will hear a double clicking as the trailer modulator valves cycle in a self test.
I always thought it was a signal to those at the back of the queue, that they’re about to get slightly closer to the pumps! 