Intermittent ABS warning

[jengledow]

I’ve got a 2015 T5.1 and have recently had it lowered and put on 18” wheels - I’ve now got an intermittent ABS fault - it chimes, the lights come on and I get an ABS fault message followed by tyre sensor not working message, the lights stay on for 30seconds to 5mins then goes off.

Firstly is it likely to be related to the lowering and secondly is there anything quick and easy I can check before going back to the garage who did the lowering or going to my usual garage to investigate? Thanks

 

[airhoguk]

It’s possible one of the abs sensors was damaged when it was lowered or it’s wiring

 

[WillWillWill]

I had similar symptoms - intermittent ABS fault that started in exactly the same way as yours, and then a sensor gave up completely. In my case it was nothing to do with lowering (or anything, it just happened).

Two main possibilities to rule out:
- A sensor is stuffed and needs replacing. This will show up on a scan with VCDS or similar and at least point you in the direction of which corner is causing the problem. Fairly easy to fix - they don't cost a lot and whilst the old one will probably have seized in you can just wreck it out and a new one goes in its place. There are many tips on how to remove an old one but I used a gas soldering iron to melt around the edges of mine and it dropped straight through. Saves smashing about with punches and whatever and damaging the sleeve it sits in.
- Wiring problem. As above - you know which corner to look at if you find that a sensor is not the problem (sadly they will both show up in the same way on a scan). Could be damaged and you'll have to look for anything obvious, but there is also known failure point with the loom just behind the rear wheel on each side where a crimp fails due to moisture ingress. This only applies if the scan shows a rear sensor is faulty. There is plenty of info and help to find this already if you do a search, but I think by 2015 this had been modified anyway, so is less likely to be an issue for you.

 

[Grim Reaper]

If you change size of wheels, do you need to reset the TPMS settings so it knows the new 'inflated' size? If the rolling circumference has changed, could the system think there's something wrong and kick out a fault code?