ford sierra abs - agrb
This is a 1988 sierra ghia automatic which I have owned from new.It has been a fantastic car and has never let me down and passes the MOT 1st time every time. Recently the abs warning light came on so I had the sensors checked.One or two looked a bit grotty so I had all four replaced. The light now goes out on tickover but lights up as soon as I reach 40mph. Have had the ECU interrogated by a Ford dealer who couldnt find anything wrong after 1 hours work so they advised that the cost of finding the fault was more than the car is worth.I take their point but as I am in my early 70s dearly wish to retain the car.Can anyone suggest where the fault lies.I obviously do not want to go to the expense of a new ECU -that would be a bit OTT as the work so far has cost over £500. Any advise would be appreciated.
ford sierra abs - RichieW
Try the owners club. They have a friendly forum with lots of technical stuff and you can ask your own queries. I found the solution to a non functioning radiator fan there recently. It was a common problem, maybe yours is too?

www.callumw.com/fsocforum/
ford sierra abs - Andrew Moorey (Tune-Up)
Are all the tyre the same size and reasonably similar on wear? A significantly different tyre will cause an error when the brain compares the individual wheel speeds and finds one different due to the rolling radius. Check also the toothed rotors on the hubs, had a car recently where the toothed ring had been distorted by rust causing an erratic speed signal triggering a fault.
Andrew


--
Simplicate and add lightness!!
ford sierra abs - Civic8
That can also be caused by fluid level very slightly down.just a thought.?.and is common on sierra.or was.
--
Was mech1
ford sierra abs - Civic8
Forgot to mention Andrews post.one to check out.
--
Was mech1
ford sierra abs - Sooty Tailpipes
As well as the other things, try driving with a high electrical load, such as heated screen, lights, full blower etc... I have seen problems on other cars due to the alternator giving too high a voltage, setting red herring "Supply voltage too high" on other systems such as engine management.
ford sierra abs - agrb
thanks to everyone who responded to my query-certainly lots to check out!!