ABS Problems

[outbound]

Hi Everone, this is my first post, having just joined and I own a Freelander 1 diesel L engine and a Series 3 88 Land rover. I look forward to using this site.
Anyway here is my problem with the Freelander. I have had the car for 7 months now and have been very happy with it. The only problem I have is with the abs. The problem happens normally about once a month
but it has happened 3 times in the last week. When you start it up the abs light stays on and you can hear the modulator running continuously even with the Ignition off. When you try and drive and brake you get the same noise as if you were skidding and the abs was working normally. I have tried braking hard, keeping my foot on the brake pedal hard and eventually the noise stops. You then switch off the ignition, start up again and the lights go out. I know the the modulators are expensive and have been hoping it might be a doggy abs wheel sensor of a sticking relay or something else. This problem only happens apart from once from start up. The system works fine as when we had all the snow and the HDC also works fine. Any ideas please, Thank you, Jeff

[carbore]

Hello,

It "could" be a sensor, I had a very similar fault on my golf and it was a sensor. To diagnose I fortunatley had propper diagnostics, but I also learned a trick doing some research.

On each sensor, disconnect it and measure the resistance with a multi meter, you should get a resistance as opposed to either fully open or dead short. You need to compare the results with matched sensors (e.g. both front, both back) as they may be different front and rear. Although my diags set showed me the faulty sensor, I check the resistances wiht a meter and low and behold it worked as I have described.

Give the ABS ring etc a good clean while you are doing this and check the wires on the sensor for chaffing/crud.

If thats no good then you can check the fit of any loom plugs on any ABS related wiring you can see and even give it a clean if its cruddy (oil contamination etc). After that then id suggest a trip to a dealer/specialist for a diagnostic check. If the main ABS is fault, look online as there are some good places that specalise in refurbs (My father had a very good experiance with one for a Citreon he had.)

Good luck

[outbound]

Thank you carbore, I will try all you have said, you have also made me feel a bit better. The problem hasn't happened since my post. So that is why I was hoping it maybe not to serious.
Thanks again, Jeff