Disco 1 abs light on!!!

Hi. The abs light on my disco tdi is permanently on. Also the brake pedal is quite spongy. Pressure bled the system but this has made no difference, also if you put your foot hard on the brake you can feel the pedal slowly moving towards the floor!!!! Done the obvious and checked for leaks etc.
Any ideas please???????

Well been out and tested all the abs sensors this morning with my multimeter . Had it on the 2k ohm scale and got a reading of 0.968 k ohms across the terminals on 3 of the sensors but nothing on one of the rear ones so i assume that's the one that's knackered? Am i right and did i test correctly before i start spending money????

Not sure about the poor pedal feel but I have had the light on due to a sensor out of position(Light tap with hammer to re-seat) and corrosion on the terminals of the ABS relay - the big black one by the engine fuse box. Cleaned the terminals and greased them and the light went out (in the correct manor - i.e. at 5mph after start-up).

Has your fluid level gone down? Might indicate a leak somewhere that is being sensed by the ABS - I don't know how sophisticated the system is (But I can guess!).

Good luck!

No fluid leaks. Thought it may be master cylinder causing pedal pressure to fade away but only does it when engine running!! Surely if master cylinder was faulty pedal would fade away with engine off as well due to fluid getting past the seals in the master cylinder???

poor pedal would be air in the system or poor m/c seals, vac assistance with engine running would show up fault more ,as does ,does fluid splash back in reservoir when pedal pumped has res got black deposit on the bottom ? if so new m/c would be useful

Thanks. I'll take a look tomos

Gave up trying to bleed the system so booked it into landrover solutions nr canterbury.(highly recomended btw) Only cost me 45 quid and brakes are spot on now. Abs light was a faulty wheel sensor, got a used one for 20 quid and sorted that myself so i'm well happy!!!