Got an ebs yellow warning fault showing on dashboard been plugged into laptop (davie equivelant program) got fault 21-37 problem on wires 4622 4623 volt meter saying 4.8 volt on the end of the plug fitted brand new wheel sensor cleaned ring up. Any ideas what to check next or where to look please

Colin, December 2013

hi I have a ebs fault on a daf xf 105 its says its pin b12 b306

pedro, February 2016

Hi Norb,

Been a bit manic with work so didn't have a chance to do anything else on my EBS 'till yesterday (Saturday) and the good news is fault found & EBS warning out!! Wired the sensor straight to the plug, ran the truck across the yard & the warning went off, so knew it was something in the loom. Had the loom stripped out & down as I've had a couple of places that have rubbed & I remember a very slight rub through on the grey & black twisted wires, so went there first. Wires were ok & it was the black wire but these were the nearside feed which was working fine. So I thought go to the drivers side & check back as you said that's another place they're prone to go in. Don't know if all DAF's are wired the same, but the cable on mine passes acoss the brake chamber & was cable tied to the centre nut, the cable felt funny as I ran my hand over it, could feel a bump & a dip, so carefully cut in & found both wires broken. Done a repair with a couple of heat shrink connectors.

Reference to coolant level sensor defect warning, parked truck on a slope & dropped the suspension right down, got about 3.5 litres of coolant in but still had the warning! Was getting a reading of 12 volt going into the sensor, whether I've disturbed the wiring as I wasn't getting any voltage reading last week, maybe it'll sort itself, time will tell.
A big thank you for all your help has been truly welcome, I defo owe you a drink mate :-)

Colin, December 2013

The ecu will probably see the 4 sensors with ign switched on ,but as the wheels rotate the sensor generates an AC voltage ,which if the wiring is faulty the ecu may not be seeing the correct voltage..Another cause may be the air gap between sensor and exciter ring just make sure sensor is fully home ,also any no matter how minor it is any damage to the exciter will throw up a fault though mainly at speed..
yes the abs valve is the one your thinking of bolted to the chassis opposite the wheel 2 air pipe connections with one going to the chamber and 1 electrical plug..At the bulkhead plug terminal 2 and 3 is the front left sensor,which is wires 4620 and 4621...terminal 8 is 4622 and 9 is 4623....if you mix 2 with 3 it will be ok..the power is confusing as the wires for the sensors should be dead,ac current is only generated with the wheels moving..any current on those wires when he wheels are not moving is an issue..if you put your meter on 4620 and 4621 ,set the meter the AC ,jack up and spin the wheel you will have a voltage reading .then do the same on 4622 and 4623 the faulty one

ref the level sensor,when topping up the coolant dump all the air out the suspension and if possible have the truck pointing up a slope.you will find after 30 mins you can get more coolant in...the coolant sensor is wired directly to the vic ecu

norb, December 2013

That's what i thought with the sensor, trying to keep an open mind on it all. I shall check that tomorrow in daylight when I get a chance, was thinking of wiring direct from bulkhead to the sensor just to see if it took the warning off the dashboard more than anything else. It was an intermittent EBS fault for a while, could go weeks in between or a day, but it cleared when ignition switched off then restart & move off again, but these last couple of weeks the yellow warning is on all the time. When you say abs valve is that the modulator bolted to the chassis? Had my chassis painted last year & they shot blasted through these wires, have had to try a few different connectors, as I thought at first this might be the problem, hoping I got the plug wired up correctly, shows power to connector 1 & 3 with neutral to terminal 2, would having 1 & 3 wired incorrect cause a fault to the wires on the speed sensor? Got coolant level sensor defect showing on dash, my old one fell out & bounced around the viscous fan, chewed some of the wire up, I've put a new level sensor in & new section of wire but fault still showing & getting no volt reading at sensor.

Colin, December 2013

I;ve never known a new sensor be faulty..

With the sensor disconnect at it's plug ,,(also have a look at the pins for signs of corrosion) at the bulkhead plug disconnected,put a split pin between wires 4622 & 4623 and check the resistance at the flylead end ,should be very low ie 1... So before doing anything hold both you leads together and note the reading,that should be the reading you should get when you put the you meter over the flylead end with the split pin in the main plug joining the 2 wires together,if you get a higher reading you have an issue ...Normal places to check is at the ABS valve ,and at the looms where the bend when the cab tilts as it chaffs on brackets

If it's definitely got a open circuit just rewire it from the bulk head to the sensor

Was only wondering as I am used to DAF codes ..

norb, December 2013

Norb,

Really appreciate the help so far thanks. It's a green plug 78c at the bulkhead, disconnected the plug, found the relevant wires, getting a multimeter reading of 1.2, checked both wires against the white bulkhead & getting zero resistance reading, checked both wires with my EBS tester & that was saying open circuit on both. Disconnected the wheel sensor & repeated all the above steps, showing no resistance reading & open circuit. Getting a green light on the sensor tester to say the wheel sensor is ok, but even though it's a brand new genuine DAF part only just fitted, am I right in thinking that could be at fault?

Colin, December 2013

can't remember plug colour ,it will have black and grey twisted wires I think ,they will have white labels with the wire number on it

norb, December 2013

Undo plug at bulkhead ,with multimeter oner the 2 wires you should have approx. 1.2 ohms..Next leave 1 probe in wire 4622 and put other probe on the large white earth on the bulkhead, it should read open circuit..If it does read open circuit, it is ok ,do the same with wire 4623..again it shoud read open circuit

If either give you a resistance reading that is the wire at fault

Next disconnect the sensor at the wheel..redo test at bulkhead ,if all is ok now then the sensor is at fault and is eathing out,if you still have a reading with the sensor disconnected then the wiring is at fault....There is a factory join in the loom roughly beside the abs valve.cut that and recheck to see if the flylead to the sensor is faulty or the loom from the bulkhead to the flylead ..Then yu know if you need just a flylead ,or if you need to find the break in the loom

Or if you don't want to open up the loom ,buy a flylead from the dealer and some rubberised 2 core ,some heat shrink , pins,cable ties and just rewire it from the bulkhead to the sensor..The light will go out when you hit about 7 kph if all is ok ,if it doesn't instantly go out

norb, December 2013

Hi Norb,

Should there be no ohms reading on either connection, I've a feeling the negative wire is earthing out & not returning back to the ECU. was going to check where the wires come out of the cab on the n/side, any idea which plug controls the EBS, was going to connect my EBS tester in the plug.

Colin, December 2013

4623 and 4622 is the right hand front ..have you checked with a multimeter using OHMS to see if any of the 2 wires are shorting to earth

norb, December 2013