XJ40 ABS problem

[Hooli]

I thought I'd fixed the ABS issue on my '40 by replacing the dodgy OSF sensor, I cleaned all the sensors at this time. For a week I didn't get a warning light up at all, now it's started coming on & going away again while driving. I'm beginning to think it's related to a relay powering the system as I've also got an issue where the radio, heater & heated rear screen doesn't always get power when the car is switched on. I'm figuring dirty connections within the ignition switch as turning the car of & on again can fix it. Sound reasonable?

My other theory is how old the brake fluid is, it's black. Could the ABS be tripping if the pump can't keep the system up to pressure? I think the first option is more likely (or another faulty sensor) as it does seem slightly related to corners & bumps as to when the light comes on.

I know the fluid is buggered, I'm going to change it. Last week when I cleaned the sensors I soaked all the nipples in WD40 ready to do so.

[Captain Cadillac]

Is this an early car? If so, did you check the overvolts relay in the boot? These are famous for losing their solder joints on the circuit board inside the relay. A quick resolder usually fixes them.

[Hooli]

Late, battery in the boot car.
Solved now (almost) with help from xj40.com.
Soldered up the main connector in the ABS ECU, got the fault codes off to clear them, drove it for 200miles ish & got the codes again. Seems it's an erratic OSR sensor, so I'll clean that up when I take the hubs off to regrease the bearings.