Faulty Abs (activating at low speeds, brake + abs lights)

Lyle · 3rd October 2021, 00:19

A weird one for someone who's an expert or has had similar problems with this area of the car.

Essentially for the last couple of months my abs has been kicking in unnecessary when braking below about 25mph. I have just received the car back from my local garage after a week of attempting to find the fault, to no avail. They have told me they are completely stumped. At this stage I had no warning lights showing but when hooked up to diagnostics one of the abs sensors was showing a fault, so they changed this, problem persisted. They said one of the other sensors also looked a bit nackered although not showing faulty so they replaced that too. Issue persisted. Although the car passed its MOT recently they said they also replaced 2 of the wheel bearings as they looked a wee bit worn incase this was causing any problems but with no luck. Readings from the sensors were checked and all 4 wheels showing the same wheel speed so would not expect abs to activate. They came to the conclusion that the pump is the only thing left that could be playing up but weren't convinced so recommend since these are expensive that I live with it for a bit and see if it gets any better or worse as the car is completely safe other than the annoying feedback through the brake pedal at low speed.

For context, it failed its mot in July for uneven brake wear. When the garage got the car back from the Mot test centre they said my back left brake was sticking slightly so replaced that caliper. It was shortly after this had first been done that I noticed the feedback through the brake pedal (don't know if this is relevant or not).

For some extra complication, after having had this issue since the end of July with no warning lights whatsoever, today, about half an hour into my first drive since getting the car back, the abs, brake and airbag warning lights come on?? Don't know what to make of that. I have had airbag warnings before as the connection under my seat isn't great so it's possible that was just due to adjustment for the mechanics at the garage then back to me again but having 3 big lights flash at you in quick succession is a bit unnerving. Car was still driving perfectly though so suspect this to be some sort of electrical gremlin somewhere.

So basically, does anyone have any suggestions as to any potential solutions?
Also, out of curiosity being no expert myself, could the fact an abs warning light has now triggered actually help with fault finding because this may now show up on diagnostics?

(I should also add that this isn't a case of a garage taking me for a ride as is often mentioned with such issues because despite having replaced the 4 parts mentioned and had the car in the workshop for a week suggesting a significant amount of fault finding labour, they refused to take a penny from me because they had been unable to fix my problem).

Thanks in advance for any suggestions or comments

3rd October 2021, 00:19	#1
Lyle Newbie MG ZT Join Date: Jan 2021 Location: Glasgow Posts: 14 Thanks: 7 Thanked 0 Times in 0 Posts	Faulty Abs (activating at low speeds, brake + abs lights) A weird one for someone who's an expert or has had similar problems with this area of the car. Essentially for the last couple of months my abs has been kicking in unnecessary when braking below about 25mph. I have just received the car back from my local garage after a week of attempting to find the fault, to no avail. They have told me they are completely stumped. At this stage I had no warning lights showing but when hooked up to diagnostics one of the abs sensors was showing a fault, so they changed this, problem persisted. They said one of the other sensors also looked a bit nackered although not showing faulty so they replaced that too. Issue persisted. Although the car passed its MOT recently they said they also replaced 2 of the wheel bearings as they looked a wee bit worn incase this was causing any problems but with no luck. Readings from the sensors were checked and all 4 wheels showing the same wheel speed so would not expect abs to activate. They came to the conclusion that the pump is the only thing left that could be playing up but weren't convinced so recommend since these are expensive that I live with it for a bit and see if it gets any better or worse as the car is completely safe other than the annoying feedback through the brake pedal at low speed. For context, it failed its mot in July for uneven brake wear. When the garage got the car back from the Mot test centre they said my back left brake was sticking slightly so replaced that caliper. It was shortly after this had first been done that I noticed the feedback through the brake pedal (don't know if this is relevant or not). For some extra complication, after having had this issue since the end of July with no warning lights whatsoever, today, about half an hour into my first drive since getting the car back, the abs, brake and airbag warning lights come on?? Don't know what to make of that. I have had airbag warnings before as the connection under my seat isn't great so it's possible that was just due to adjustment for the mechanics at the garage then back to me again but having 3 big lights flash at you in quick succession is a bit unnerving. Car was still driving perfectly though so suspect this to be some sort of electrical gremlin somewhere. So basically, does anyone have any suggestions as to any potential solutions? Also, out of curiosity being no expert myself, could the fact an abs warning light has now triggered actually help with fault finding because this may now show up on diagnostics? (I should also add that this isn't a case of a garage taking me for a ride as is often mentioned with such issues because despite having replaced the 4 parts mentioned and had the car in the workshop for a week suggesting a significant amount of fault finding labour, they refused to take a penny from me because they had been unable to fix my problem). Thanks in advance for any suggestions or comments