Xantia ABS disaster

[aerodynamica]

Yonks ago my Xantia started showing an ABS fault. It would start normally with the ABS check light going out after the engine starts and it stays out as normal. However after driving about a mile the ABS light comes on and stays on. I'd read about a similar thing before that turned out to be corrosion on the toothed ring giving a bad signal to the ECU so I checked all 4 rings and after a brush up the fronts looked fine. I can't get the Lexia to talk to my Xantia - only the C5 but I had a pin out diagram of the ABS multi plug to test the resistance on the 4 sensors. All 4 read correctly so I was at an initial loss as to what was wrong. With the MOT in a month and a half I wanted to get it fixed but was not sure what the issue was.

I have also changed 3 of the 4 ABS sensors over the years and finally had the last one to change so decided to change it anyway regardless of any real cause.

It's the rear left sensor to change and also a chance to free up the very squeaky rear brake pads with a bit of copper grease.

SO off with the wheel, pads, disk etc to access the ABS sensor and what I found was a surprise!

totally sheared off ABS sensor!

it's gone!

You can't see the rear sensors on the Xantia unless you remove the backing plate and the disk so I couldn't see this. It also still had electrical continuity and the right resistance.

But what happened? It soon became clear! I'd changed the wheels on the car last August to refit the Peugeot Nimrod wheels after getting them powder coated and the other alloys used taper seat bolts while the Peugeot wheels use flat washer type bolts. The Peugeot wheels need 10mm spacers to get the right offset and longer bolts. I had fitted the other alloys with new wheel bolts temporarily before cutting the length of them down by a few mm for a test drive in the 4 storey car park here so I only traveled about 30 meters that day and that was when the ABS light came on suddenly. I'd obviously fitted a bolt that was way too long and reached all the way in and fouled the ABS sensor and of course totally destroyed it after one turn of the wheel.... It was because the front wheels are limited by the length of the bolts' protrusion because of the hub structure but at the rear the bolts protrude into open space.... well except for the ABS sensor.... so er, there you go. If you have an oversized wheel bolt ready to trim down to fit the front.. don't fit it on the back!

new one in!

All now good and lesson learned..

[RichardW]

Busy few days in your workshop! Easy sort of mistake to make. I misrouted the cable on the rear of mine when I had the susp arm out and rubbed it through on the rim. Light would come on in the wet. Remarkably it continued to work once I taped it up and tied it out the way.

[aerodynamica]

Busy few days in your workshop! Easy sort of mistake to make. I misrouted the cable on the rear of mine when I had the susp arm out and rubbed it through on the rim. Light would come on in the wet. Remarkably it continued to work once I taped it up and tied it out the way.

Ah, easy mistake to make! To be fair thought the routing of the wire isn't great at the best of times...

[white exec]

Gosh - Not something you'd suspect when re-fitting some wheel bolts.
The resistance detected must have been a fluke reading (no pun intended).

[aerodynamica]

Gosh - Not something you'd suspect when re-fitting some wheel bolts.
The resistance detected must have been a fluke reading (no pun intended).

Hi Chris, yes that had me puzzled. I think that although the sensor was totally wrecked the physical coil was still intact and it was only the metal prongs within the plastic surround that were broken off. At least that's all I can think of. The sensor became even more destroyed in order to remove it though so no post mortem available!