[thommo41]

OK, in the snow and ice, I set about removing the front wheels to test the ABS sensors, as the TC light has been lit on my puma constantly, so no ABS.
I took the sensor off at the connector end, under the wheel arch, and tried a fluke tester on both pins. I got NOTHING on the readout. I tried the other side, same result. The chances of both sensors being dead is fairly slim I'd of thought? Am I doing something wrong?

TIA, Alan

[Mangham54]

What were you testing with and for?

Multimeter? Resistance?

You are looking for circa 1Ohm. Did you also test the sensor's plug, not the loom connector. If both sensors are dead, check the voltage from the loom - as that could be too high and buggering the sensors.

[JohnC]

Make sure your Fluke is set to measure resistance and in the right range.

A good sensor should be about 1.1 K Ohms.

[thommo41]

Thanks for the replies... The Fluke automatically sets the range I'm told, so it's not something you can set. It was set to Ohms. We unplugged the sensor from the car (ie the lead under the wheel arch liner) and then tested the pins on the sensor itself. Nothing either side. The car connector wasn't tested as far as I remember (my mate did it to be fair). Do you think both sensors could be dead? I bought the car, it drove fine for a couple of months with no issues, it then started with intermittently leaving the light on lit. Sometimes it would go off but now its on every journey. I might just pay the tenner (ebay) for one sensor, then test that. I assume that should show like 1 Ohm? If that does, then I guess it's 2 dead sensors, but if not, the tester is to blame?

[JohnC]

It's unlikely both sensors have gone. I would re-check them mate.

If you do buy a new sensor, be aware the lights won't go out until you drive the car and the ABS does a self test. You can't just slave one in.

And they should read 1.1 K Ohms. That's 1100 Ohms, not 1 Ohm!

This post has been edited by JohnC: 26 January 2013 - 10:02 PM

[thommo41]

OK, finally got round to spending the time to sort this out...

As mentioned, both sensors appeared to give no reading, but I figured it was pointless doing both, so did the passenger one first, then test drove. That sorted it, so just the one sensor at fault afterall I guess! So always start with the kerb-side wheel, the most likely to get dirty!
It's been discussed at length how to do this, but just for the benefit of anyone who is also crap at DIY...

- Jack up the car, secure with more than just a jack though, just incase!
- Turn steering to get better access to sensor, full right lock for the passenger side
- Remove wheel
- Remove wheel arch liner, plenty of torx screws, easily part
- Drench the sensor mounting bolts (1 at top, 1 at bottom) with WD40 and leave to soak
- Take mental note, or pictures, of the sensor cables routing
- Pull the sensor "plug" out of the loom, at the top of the wheel arch. Pull the 'rubber boots' from the sensor cable out of their retaining clips. You should be left with the 2 bolts that you should of lubed up earlier to attack next
- These bolts will probably be really corroded, see how you go, be patient and re-lube with WD40 if necessary
- The top one came out well, 8mm socket I think, don't quote me on that though
- The bottom one is a longer bolt, it was stuck hard in mine, but I eventually got it to move without breaking or rounding off, with liberal use of more WD40
- One the 2 bolts are out, you're left to remove the sensor
- If it's like mine was, it will be stuck solid, won't shift at all. This is the only real problem, and it took an hour or so to get this out, and new one in...

1. Try mole grips on the sensor, it's weak plastic though, try and wiggle side to side.
2. Mine wiggled from the inner side, but the shaft bit that poked through the hole, the working part that has the magnet/coil bit, that was not moving. Now I had to remove the brake caliper and brake disk to get access to the hole. Screws/bolts on the back, full left lock made getting to these easier
3. Decided to snap the connector off using mole grips, sensor cable came away, leaving the "shaft" and coil stuck in the hole on the wheel hub. DOH!
4. This part of the sensor has weak plastic around it, with a harder core, very difficult to shift. Tried lots of things, eventually made progress by bashing the shaft through from the inner side, using a small socket set as a "chisel"
5. Still left with bits of the sensor in the hole. Used a drill bit, manually not with a drill :-D, to work the plastic and gubbins out of the hole
6. Don't be tempted to lever it out against the metal "hub/disk", it tended to bend, this will mess up the surface that the sensor gets it's resistance from, probably more harm than good
7. After much persistance, and a little bit of carving away with a knife blade, the old sensor came out
8. New sensor WOULD NOT go in! DOH!
9. Much lube, no help
10. Carved away, and sanded/filed lots of material away from new sensor shaft, after lots of messing around, I got it in, still very very tight though
11. Wiggling it in got me a little further, not far enough in to get the bolt in to pull it into place though
12. Gave in and used mole grips to gently squeeze it into place
13. You're about done then, bolt the sensor end into place (use some grease/copper slip incase you need to do this ever again!), then re-fit sensor using the path that your memorised earler ;-)
14. Re-fit the brake caliper etc, re-fit wheel, then roadtest. Don't forget the wheel arch liner, and check and double-check that you aren't left with any stray bolts or washers you forgot to fit!

If I did it again, I'd probably take more care to get the sensor out without snapping it, assuming you can do that, it's an easy job!

I'm happy now anyway, hopefully the car is now a candidate for another MOT and another 12 months happy motoring!

Cheers, Alan

[nytram]

well done ,i know how hard they are i have just done my freelander abs ,all my lights came on and it was only one sensor if i have to do the puma i think penatrating oil soaked in for a day helps but well done anyway />