850 T5 ABS Woes Topic is solved

Cookeh · Post by **Cookeh** » 15 Aug 2019, 13:41

Sublime, thank you.

Cookeh · Post by **Cookeh** » 17 Aug 2019, 11:18

Here are the results from the wiring testing:

LF 1308
RF 1109
LR 1100
RR 1088

This would seem to suggest all is well there? Though the sensor that has previously shown an error is significantly different from the others and approaching the limit.

Cookeh · Post by **Cookeh** » 06 Nov 2019, 05:12

This issue has resurfaced again. On this occasion it was preceded by the pump cycling and hissing throughout the whole drive (everything between a 5min drive and a 2hour drive), and the ABS would kick in through the pedal on light braking. It would not trigger on heavy braking, and additionally only seemed to occur at speeds up to 20mph.

I'm still getting ohm readings similar to my last post, and the car has a module that has been repaired less than a year ago. Do pumps on these fail? Is there anything to fail? Or because the ABS is triggering does that suggest it has to be an electrical error.

Post by **abscate** » 06 Nov 2019, 05:14

Have you had the wheels off and inspected the tone rings on each wheel? It will only take one bad one to convince the car a wheel is slipping and activate ABS

Cookeh · Post by **Cookeh** » 06 Nov 2019, 12:44

The rears are clean and undamaged, addressed those when sorting the handbrake.

I haven't checked the front rings as the ABS sensor bolts are truly seized and I haven't been able to crack them loose yet. I will do this as a priority though as it seems like the only thing left to rule out.

Post by **Clemens** » 08 Nov 2019, 05:44

what year is your T5? 96 up or earlier?
I'd definitely check the front rings and also again for bad wires.
for years my 95 had the issues you describe intermittently, usually triggered by rotating the steering wheel to full lock. So there must have been stress to the wire or connector.
Maxbe lift the front wheels up and have someone turn the steering wheel while you measure the reistance of the front sensors?

Cookeh · Post by **Cookeh** » 08 Nov 2019, 06:23

Clemens wrote: ↑08 Nov 2019, 05:44 what year is your T5? 96 up or earlier?
I'd definitely check the front rings and also again for bad wires.
for years my 95 had the issues you describe intermittently, usually triggered by rotating the steering wheel to full lock. So there must have been stress to the wire or connector.
Maybe lift the front wheels up and have someone turn the steering wheel while you measure the resistance of the front sensors?

MY96 on a 95 registration. The issue did used to only occur on full lock, but now its more random and far less intermittent. I definitely did have an issue with cables being stressed, but I rerouted the cables and haven't seen that issue since (been 3 months since, and that issue used to reset itself after each drive cycle). Will add it to the check-list though as no harm in doing so.

Post by **Clemens** » 08 Nov 2019, 11:01

if it is a 96 MY: check the big black insulated wires that run to the ABS module. The insulation tends to crack on these wires, oipening up room for corrosion. A few months back my ABS light came on after already resoldering the module twice a few years ago. Upon inspection, the insulation had crumbled and the copper had corroded green. I sprayed WD40 (or sthg. similar) on the wires and the problem was gone.

Edit: Maybe this bad insulation can be found on earlier 850ies as well, but definitely on 96 up.

Cookeh · Post by **Cookeh** » 08 Nov 2019, 11:10

Thanks for that, another thing to check!

Cookeh · Post by **Cookeh** » 09 Nov 2019, 13:55

Didn't get time to check the reluctor rings yet (crazy rain in my area!), but I did get 30s to check the wiring. Is this the insulated cable in question? If so, you may well have been spot on the money.

850 T5 ABS Woes Topic is solved

Re: 850 T5 ABS Woes