always wise to change the exciter ring with the hub off ,it only takes a small dent which is barely visable to put the light on,this will generally happen at high speed, also good idea to make sue the sensor moves…th clout with the hammer I guess was to knock the sensor in ,hence the clicking would be the sensor running over the exciter grooves / segments,also if it is a single nut holds the hub on then that is a 1 use nut.to stop any future issue I would put new exciter ring on and make sure the sensor moves
the self test just checks the abs valves operate
norb:
the self test just checks the abs valves operate
Ok, I just wondered if the test failed if it just keeps cycling through and there’s a cut off parameter to stop over a certain wheel speed based on it was ticking (ie cycling through test again and again) then stops testing over 5mph because the brake system may be needed to be used in anger at that point.
Sounds more likely now that the sensor’s just not contacting the teeth any longer through use.
norb:
see Tarmac Duck we dealer techs aren’t that bad ,glad you have got there in the end ..DAF do have a self test would like to think I have a reasonably knowledge of how DAF 's work though the previous poster apparently thinks tucks don’t self test…but we all lean something new daily
So my original comment about it being the ABS self test was (at least partly) correct then? 
I:
Sounds like the ABS self test.
Unfortunately the ticking has started again. It is a very rhythmic just as before. This afternoon I disconnected the abs sensor from the suspect wheel. This put abs/transmission warnings on the dash but the noise stopped. Is it simply the sensor is not working, but whilst it is connected there are no warnings. Any more thoughts please ?
Tarmac duck:
Unfortunately the ticking has started again. It is a very rhythmic just as before. This afternoon I disconnected the abs sensor from the suspect wheel. This put abs/transmission warnings on the dash but the noise stopped. Is it simply the sensor is not working, but whilst it is connected there are no warnings. Any more thoughts please ?
It could be the exciter ring’s not on true. If you take it to any half decent workshop they should have kit to plug in to the sensor that will test the gap and everything on the sensor and exciter ring side of things are as they should be by jacking the wheel and spinning it by hand. I’d do that next to eliminate all that and work from there. Possibly when you pulled the sensor plug out it’s pulled the sensor away from the teeth.
Also things like dust guards can sometimes not catch when the wheel is jacked up but do when it’s loaded on the ground.
Any more suggestions please. I have tried spinning the wheel by hand not a murmur. I can move the sensor with a pair of grips but I am frightened of making things worse that’s what usually happens when I start messing with things I don’t understand. At the moment there are no warning lights and everything else is fine.
Not much point doing anything else until you can ascertain the sensor and ring are as they should be.
If there was a problem with the ring or sensor surely my dash would display ABS. Warnings
Not necessarily if the teeth are hitting the sensor at one point and if the gap at the other is not too large no fault will occur.
Have you put a bar under it and checked the bearing/hub is ok?
This has been happening since the beginning of May, if something was catching it would be worn away by now. Furthermore like I said it is only audible at aprox 5mph. The bearing and kingpin have checked twice and no problem found. I really appreciate your thoughts keep um coming.