lotusGT3

Any chance we know how this ended as I now have the same issue, and the workshop is drawing blanks.

motojman

The previous posts ended abou April 1021 and now lotusGT3 from down under is asking about same problem.

I am reading it for the first time but have some experience with ABS systems.

Do you hear any other noises coming from the system? i.e. are there any tail tale clicking of solinoid valves operating? Do the brake work normally as expected )except for slip limited events)?

I don't know what fuse might disable the system but here are some comments...

1) The motor should not run all the time and if it does, it has limited durability - so that is not good. If you can't find a fuse to disable it, I would pull the main connector to the unit. I am assuming that the ABS light is on, on the dash board which indicates that ABS is disabled with some fault. So pulling the main connector does not eliminate any function other than the undesirable running of the motor/pump.

2) The electronic controls that operate the motor are internal to the electronics in the ABS unit. They would typically only turn on the motor when either ABS or ESC were active and required. From what I know, I would doubt that this problem would be associated with a wheel speed sensor problem. Although WSS sensors are the cause of lots of ABS/ESC faults, the constant running of the pump would not seem to be one of them.

3) I would unplug and replug in the main connector a couple of times. I can't say that I think it might be associated with a connection falut but that is a typical fault of electrical systems and connectors. It costs nothing and takes only a minute or two.

4) If there are no codes and it is not a simple electrical connection issue, it sounds like a replacement o the ABS unit might be in order. In some systems the electronics half of the unit is serviceable and you can replace the electronics without breaking into the hydraulics.

Good luck - let us know what you find.

I hope this is of some use or at least interest....

lotusGT3

Thanks for your thoughts.

I'm unaware of any other noises as I've not experienced it personally and the workshop has not mentioned anything. It can't be disabled via a fuse so the only way to stop it is to disconnect the battery or pull the ABS connector pin and the workshop is mindful the motor should not run continuously. There is a fault code ABS fault 4266 being RETURN PUMP FAULT which can't be cleared and there are warning lists on start up, and which persist.

We've essentially disconnected the ABS function for the time being to give us some time to problem solve with no time pressure as I've got a track day tomorrow. Brakes work normally but just no ABS. Taken it for a shakedown and all seems OK.

I think the units are all in 1 and not repairable and the relay is internal and yes it looks like it could be a faulty unit caused by a voltage spike.

We've been told a correctly weighted tap with a hammer might release a stuck relay but clearly that will be a last resort and possibly not a great idea as who knows what other latent damage might be caused...

Iroc02