Post Number: 47
|Posted on Tuesday, 03 March, 2020 - 20:48:
My ABS warning light often comes on especially when go over a sharp bump. If I stop and turn engine off and restart the warning light is off. Sometimes will come on a couple of times and then will stay off for a long drive .Brakes are working fine.Told sensors of front wheels maybe dirty but cant identify them.
Like some advice even photo of sensors .If desperate can remove warning globe on dash.
Post Number: 629
|Posted on Wednesday, 04 March, 2020 - 01:51:
Check your electrical connections, inc alternator, main brown cable connectors (2).
It's almost certainty an interrupted electrical supply or signal OK
I found this out on mine when I started it up with no alternator belt OK
Post Number: 593
|Posted on Wednesday, 04 March, 2020 - 01:53:
There's an ABS sensor on each wheel hub front and rear. Remove wheels one at a time and support the car securely, then follow the black wire going to each hub you will find the sensors. A small bolt holds each sensor in place. The sensors can often be stubborn to remove due to the effects of corrosion. Before going to the trouble of trying to remove the sensors check that there is no damage to the wires or corrosion at the push on connectors where the wires connect to the ABS/ECU loom. Always disconnect the battery before disconnecting any ABS sensor connections, otherwise you could cause the ABS light to remain on. If cleaning the sensors don't use brake cleaner or parts cleaner as the sensors can be sensitive to chemicals, use only warm soapy water. If you're lucky a power wash around the wheel hubs without disconnecting anything might do the trick. I had a case where a cat climbed into the engine bay from underneath on my 4x4 and a dog tried to follow her and gnawed an ABS wire in the process. If the ABS light is on it means that the ABS is not functioning.
Post Number: 594
|Posted on Wednesday, 04 March, 2020 - 01:56:
Forgot to mention that there's also an ABS relay which could be faulty or the connections to it might be corroded. Electrical contact cleaner followed by a dab of electrical contact grease might solve that problem.
Post Number: 48
|Posted on Wednesday, 04 March, 2020 - 20:18:
Thanks Michael and Larry.I have checked the relay and fuse in the fuse box seems fine and clean. Will take each of the wheels off and check the brake sensors on each wheel and just clean with warm soapy water .Luckily being Australian delivered there is very little corrosion
I assume the sensors are located near the center of the hubs hope can find them as looked once before on another Spirit without success.
Post Number: 630
|Posted on Wednesday, 04 March, 2020 - 22:55:
Post Number: 49
|Posted on Thursday, 05 March, 2020 - 18:31:
Thanks Michael excellent pictures will print off and have a go Saturday .Another Range Rover friend says loose wheel bearings can have same affect so will check them at same time .
Post Number: 3277
|Posted on Friday, 06 March, 2020 - 11:47:
Incidentally, the ABS relay is the same as the fuel injection relay on cars around 1987-1993 (mechanical fuel injection). It is essentially a standard 30-86-87-87a relay with a 22 volt crowbar zener diode. It the vehicle voltage spikes for any reason, the fuse will blow to protect the ECUs. The relays are crazy-expensive, but you can make one. The ECUs cost a bomb, are hard to come by but can be repaired.
I very rarely contribute to the Forum these days as my business is in new spare parts for R - R&B cars from 1946 to 2020.
Post Number: 3623
|Posted on Friday, 06 March, 2020 - 17:42:
I understand your situation completely however I do miss your contributions as they always contained something new to add to our collective knowledge as well as helping solve some very difficult electrical problems with the post-Shadow R-R/B models.
Best wishes for your continued business success
Post Number: 662
|Posted on Friday, 06 March, 2020 - 19:54:
Richard, certainly miss your postings on this forum.Do you have a part number for the Zener diode. and the polarity and pin number in the relay ? I have had these fail at great expense from Bentley !
Omar M. Shams
Post Number: 1950
|Posted on Friday, 06 March, 2020 - 21:25:
For those of you who dont know Richard Treacy - he is probably one of the top 5 most knowledgeable Rolls-Royce/Bentley experts in the world.
We certainly miss Richard's contributions.
Post Number: 125
|Posted on Saturday, 07 March, 2020 - 05:34:
I found that teeth that trigger the pulse around the edge of the disc got clogged with gunge/dirt etc.
A toothbrush will fit through the aperture when the sensor has been removed - a scrub with soapy water will give the teeth a clean.
From memory I didnít remove one rear sensor because the exhaust was in the way.