Abs anti lock sensor check

[robmal]

Hi all

Trying to diagnose the following problem on my 944s2 :

Anti lock warning and the red warning (!) light come on when ignition turned on and remain on whilst the car is driven

My gut feeling is that this will be a fouled up sensor with lots of rust dust. The car has stood for quite a while. Pulling the sensors is proving to be a right pain so hoping to narrow it all down by an ohms resistance check to find out which one is playing up. Can anyone remind me of the ohms reading I should be getting across the two wires from each sensor please.

Cheers

[robmal]

Aye further to the above, readings as follows

FOS 9.84
FNS 9.84
ROS 9.71
RNS 9.9

Am I right in thinking that these are all within spec or is the variance in the back readings a cause for concern?

Cheers all

[scam75]

Hi Rob

In my experience a faulty sensor brings the light on when you start moving off, not on start up. The system self tests about 5 mph, you hear the pump whirring and the sensor readings are validated at the same time.

Light on at start up would have me looking at the ABS control unit or the relays on the pump.

And yes, they are a nightmare to remove!

Stuart

[robmal]

Thanks for that, yes was just getting to that point in my understanding! So as my warning lights have been coming on straight away then the sensors aren't likely to be the cause - confirmed really by the ohms readings too.

Well I might have got away with things quite lightly... Pulling and reseating all connections, fuse and relay (in the main fuse box) seems to changed something. The warning lights no longer come on with the ignition. A road test later today may confirm my luck.

Cheers

[scam75]

Good, you are likely on to something. These cars do not like being laid up. I had all manner of silly electrical issues after a year off the road for my engine rebuild.

One fog light inop, indicators not working, a door speaker wasn't working and a few other things I think. All started to work again with a relay wiggle or two and using the car daily.

Stuart

[robmal]

Aye
A road test has confirmed that the anti lock gremlins have been sent packing. You are right about things going down hill with a car being laid up. The sunroof needs looking at, likely to be grumbling relays, and a new headlamp rotating switch was required. Apart from that, fingers crossed, all good. MOT time very soon!

Cheers

[scam75]

Good news then and good luck with with the MOT!

Mine passed at the start of the month, advisory on a misty front shock which was rebuilt by GAZ about 4 years ago, so a bit annoying. Anyway it returned back to GAZ for an inspection and it needed a new rod and obviously a service at the same time, back on the car now and all good!

Stuart

[robmal]

Thanks! We shall see, but quietly hopeful!

I went the B6 bilstein route about ten years back and have never felt the need for anything else.

All the best

[scam75]

Yeah that seems a good way to go. When I done mine, with the car lowered a fair bit, about 60mm, GAZ was my only real option without massive upheaval. And at the time the Gold kit, 4 dampers and springs, was only £550. Same kit is £1k now. The rears are untouched in that time and still good, and due to aforementioned leak 4 years ago, i sent both front units back down for a service. Possibly the rod was slightly bent at that point and had caused the leak, maybe it was subsequently bent, who knows! Hopefully be good for a while now!

Good luck.

Stuart

[tr7v8]

Aye
A road test has confirmed that the anti lock gremlins have been sent packing. You are right about things going down hill with a car being laid up. The sunroof needs looking at, likely to be grumbling relays, and a new headlamp rotating switch was required. Apart from that, fingers crossed, all good. MOT time very soon!

Cheers

When I first got mine it was my daily driver & pretty much didn't miss a beat. It did 38K as my car allowance car in 18 month. There after it did around 2-3K a year and every spring when I started to use in anger the sunroof didn't work, the windows were slow etc. After a couple of weeks everything woke up & started to work properly.

[Waylander]

Aye
A road test has confirmed that the anti lock gremlins have been sent packing. You are right about things going down hill with a car being laid up. The sunroof needs looking at, likely to be grumbling relays, and a new headlamp rotating switch was required. Apart from that, fingers crossed, all good. MOT time very soon!

Cheers

now find some grass or gravel and check it actually works, not just the light off!!!

[scam75]

Aye
A road test has confirmed that the anti lock gremlins have been sent packing. You are right about things going down hill with a car being laid up. The sunroof needs looking at, likely to be grumbling relays, and a new headlamp rotating switch was required. Apart from that, fingers crossed, all good. MOT time very soon!

Cheers

now find some grass or gravel and check it actually works, not just the light off!!!

Good point, I had a no light, ABS inoperative scenario before. Pump was seized. ECU had no idea.

[tulipstwice]

Hey mate, definitely worth checking the pump operation, even with the light working properly now.

[Wh1t3Kn1ght]

Lol the last post was over a year ago, bit late now but good advice...