ABS Light

[jagdaveh]

I've just changed the front brake discs, calipers and flexible brake hoses. Bled the brakes and everything looked fine - until I started the car! The ABS light stays on with no other warning/messages - there were no problems before starting the work. Is there something I should be doing to bleed the ABS unit as well as the calipers? I've tried disconnecting the battery to clear the fault but it makes no difference. The car has been connected to a battery conditioner so there are no issues with low voltage which I know can cause spurious problems.
Any advice/suggestions gratefully received.

[davidr]

If the car is in a driveable state take it for a quick spin. I know that the system on the late XJS will keep the light on after a fault has been detected until it is either reset using a diagnostic plug-in machine or the car has been driven at above 20km/h. If the fault has cleared the light will go off. I'm not sure if its the same for the XK8 but it's got to be worth a try!

[Astromorg]

Well, usually the best way to see what's causing a warning light is to put a scanner on it and up will pop the answer (Sometimes!) but presumably you'd have done that if you had access to one!

So, as faults arising immediately after doing work on a car are usually related to that work, I would suggest a close physical examination of both front wheel areas. I'd be looking particularly the wiring loom to the ABS sensor for any damage, then ensure the toothed wheel that the sensor 'reads' at the back of the hub is clean. Also remove the sensor itself and check its face is clean.

The harness is also well known for its wires fracturing internally where the suspension movement flexes it. It could be that in jacking the car up and allowing the suspension to go fully down, that could have been the final straw etc.

The ABS unit itself should not require any special bleeding process.

[jagdaveh]

Thanks for your suggestions. I'll check the wiring again but think it's probably ok - if I disconnect the wheel sensors I get a DSC error which goes away when they're reconnected, but the ABS light still remains. As the car is currently SORNed I will have to wait a while before I can try the driving "fix". Can you recommend a reasonably priced code reader and clearer that would confirm the problem?
Thanks again.

[davidr]

Many of us use the iCarsoft 930 as in the picture below. This is Jaguar/Land Rover specific which is handy if, like me, you have examples of both! Costs about £95. Plenty advertised on eBay etc.
This will read your car and can reset the ABS light.

[mike020150]

The ABS system has two check modes, one when the car is stationary and the other when it starts moving and reaches a certain speed. Consequently, if you haven't driven the car, it's entirely possible that the light might well extinguish after the car is driven. Mike.

[jagdaveh]

I'm delighted to report that, following a not very quick trip down my drive (about 20 metres!!) to see that the brakes worked at least a bit, the light went out! Clearly I didn't get up to anything like 20 km/h so I wasn't expecting anything to happen.

Thanks to you all for your help - it's good to know that not everything on a Jaguar is expensive to fix!

Dave

[davidr]

Cheap fixes are the most satisfying! Great to hear it worked

[mike020150]

Excellent news! Always remember the old adage, 'Simple is beautiful'. Mike.