Abs light

Hello, I have a disco 2 with an annoying abs light problem. The abs light comes on and off intermittently, it makes no difference on bumpy or smooth roads, and it will go off when stationary then come back on, I have connected it toHawkeye but it's not showing any fault codes, I have replacedboth front sensors and the wabco shuttle valve. It's not the 3 amigos it's just the abs light on its own. I have also checked the fuses are clean and the abs relay is seated properly.

Hi. It seems that there's a problem on that particular warning lamp's circuit or an ECU misbehaviour, can be a bad contact on that path.
1. Can you see all the 3 amigos after ignition on the self test?
2. Do you have RAVE ?

Hello, no don't have rave, just a PDF workshop manual, and on self test all the warning lights light up, before going off as they should. My best guess at the minute is a dodgy or loose connection somewhere, but finding it is a nightmare.

yes, diagnosing such thing is hard, remove the dash binnacle as to have access to the connectors(it's easy) then you have to be handy and do somehow to hook a multimeter to C0233 pin 3(white/red wire) in situ(i attach the connector view, concentrate to identify the correct pin), insert a thin wire into the pin from behind and measure on that) put the multimeter as to see it while driving to observe if the voltage drops or not when the ABS light comes on, The ECU delivers 12V to extinguish the light and when that 12V drops the light comes on...if the voltage stays steady while the lamp comes on the problem is within the IP, if it drops is between the ECU and IP or within the ECU, and we'll speak again... what year is the vehicle?

After having another look around this morning , alarm bells started ringing as when I checked the ECU under the Bonnet,(for oil ingress) it has been replaced from a Breakers at some point, maybe the previous owner was attempting to rectify this abs issue, or maybe the replacement ECU was faulty to start with. I have a spare ECU, which came off a 2004 ,( mines a 2000) not convinced it's an ECU problem personally, just thinking out aloud

The engine ECU(ECM) has nothing to do with this, when i said ECU i meant SLABS ECU cos that's the ECU involved in ABS. And btw a 2004 ECM is not suitable for 2000 year engine, download the attachment for future electrical troubleshooting

may be useful

Thanks for all the replys, another light has now come on, which is the hill descent light on the bottom left of the dashboard, I briefly plugged it in to Hawkeye, and will report later what the fault was, the abs seems to be on permanent nos..oh joy

After plugging Hawkeye in, the hill desent light dosnt show any fault codes, just the same as the abs light, it seems aliitle bit of a coincidence ? I read another thread that the hill descent can be switched off, if so how ? Thanks

You get no fault codes cos the problem is on the warning lamp's earth path... now to HDC is the same like for ABS which i told you how to diagnose few post before

Thanks for your reply, as both abs and hdc are not on all the time, I will have to wait until they are permanently on, no point trying to find out what's going on when they are off..I.e working correctly. Thanks again

As long as it's a bad contact or dry joint issue they might not stay on permanently too soon