Im having problems with the abs light which keeps coming on the dash.

I took my car to central day on way there and back the light stayed off.
Drove to work the next day bloody light came on.I cleaned both rear sensors and pick up ring and osf the other week.The light come back on.I removed the nsf drive shaft and the pick up ring was covered.in grease and shit.Cleaned that and replaced the sensor.

The light stayed off for 1 day then come back on lol.

I start the car up both lights go out.When im braking the pedal is pumping on my foot slightly then the light will come on.Also i could be wrong but where i live there are a few speed bumps,when i go over these the light sometimes comes off. If i slow down the light will go out.Also when i go round corners this will bring the light on too.


Could a abs sensor be faulty.I thought if they were faulty the light would stay on from start up????

Is there something i can make that i can plug into the abs diagnostic plug to see if i can get flash codes out of it.

Any help would be great...And no im not taking the bulb out..

 

Great title Glenn Mate, so not like you lol

 

Its just pissing me off now.Ive had nowt but chew with the abs over the last few years.I repaced the rear sensors a few years ago cause they had corroded and ive changed the nsf sensor cleaned the.shit of the ring (ow eeerrrrr) and its still playing up.

Ive got some technical if on the system so im gonna check for resistence on the sensors later on.Ive got a few spare sensors incase its on of them.

 

If one of the sensors was out of spec the light would stay on from is initial test period when you turn the ignition on. It will be a sensor not picking up properly I'm sure you can measure the ac voltage across the sensor when you spin the wheel. I can't remember of the top of my head what sort of result you should get though.
Do a search for posts containing abs by a bloke called jon@work I'm sure he had posted up some good technical info.

 

Check the condition of the wiring and plugs too glen. Years of being blasted at with salty water will corrode them.

 

Also worth changing the relays under the passenger side dash

 

I would say it's a loose connection or sensor fault, by the fact the light comes on and off with corners etc you should see at least 1K resistance on each one.

The pulsing you are getting is the ABS activating.

Martin

 

Is the brake fluid level in the reservoir high enough? The ABS module also checks it and if it senses a low level the light will come on. This can quite well be the case when it comes on during braking and cornering.

 

I had the same thing. Sometimes it woked, sometimes it didnt. When it stopped working the car would not brake at all with a solid pedal or would just lock up with the faintest touch. Scarey!

That turned out to be a sensor in the end. just had to buy one and swap them round until it was cured. That took a while because it was so intermitent.

 

Yeh i always thought if the sensor was faulty the light would stay on.I got the info of jon and someone else off here.

 

I will check them when i look at my car.I couldnt be arsed to look at it today.

 

Thats what i thought matey. I will check the resistance soon.It would be ideal just to plug something into the diagnstic plug on the abs ecu to see which side it is.

 

Im almost certain it on the max mark if not higher.Im sure i swapped the fluid level over too.

 

only the escort cosworth supports diagnostics
despite what you read the sierras don't have any
measure the wheel speed out puts at the ecu at 15mph
meter set to ac
what you should get is a similar out put for all 4 sensors at this speed
If the sensors are original fit new ones
they are antiques
you can eliminate the faulty level sensors by simply bridging the connectors on the white loom plug

 

I always thought they had one for the ecu. The sensors i have replaced have been secondhand but they look like good sensors.I will have to check the resistance then go from there.

I will have to get all 4 wheels off the floor to check they ar picking up the signal from the pick up rings.

 

Checked the resistance off all 4 sensors today and they are all between 800hms and 1400.
The nsf is1043
osf is1088
osr is1040
nsr is 1039

 

you need to check the out put as per my instructions above

 

So im gonna need to jack the car up so all 4 wheels are off the floor then try and spin the wheels or start the car up and put in gear cause with it been 4x4 the wheels are a bit hard to turn.

 

no you put it on my flash 2 poster ramps and pay me to test it
alternatively you get some one to drive it down a private road and test the outputs of each wheel sensor at 15mph

 

There are 2 post tow post ramps at my work too lol.

So what will i need my multimeter to be set at so i can test them.

 

AC voltage, check at the ABS ECU connector. (disconnected)

 

do you want to borrow my glasses

 

Hi m8 when i had my 3 door i had the same problem ,mine started after i bled me brakes and i dropped my brake fluid cap done on the cross member.After that my abs light would come on for no reason ,so i changed the cap and that sorted it for me might be worth ago for the sake of a tenner

 

Glasses? I need binoculars...

 

Thanks.matey.I will have a go at doing that.Do you know what voltage i should expect to get?

 

All i can rember is i never had a problem before i dropped the cap so i new it could only be that so i never got involved with it as it was a easy fix for me .Well worth a try thou

 

Glenn - I don't know..not exactly, but it should increase voltage with speed.

If you're driving along at 15 mph in a straight line, the output voltages from each sensor should be roughly the same (As Uncle Tony has posted above)

Need to figure out which pins on your ABS ECU connector are from the sensors. Instead of jamming the multimeter probes in the connector, which can spread them out and cause poor connection,, use a paper clip or similar. (Sorry if this is teaching you to suck eggs)

It's a lot easier on modern cars where you can just view live data via the OBD socket

 

Ive had the abs ecu plug off before when i was checking resistance of the wires. I just used to plugging a computer into the car/van then spinning the wheels to see if the sensors are ok.

 

Thanks for the info matey.

 

you can clearly see which wires are the sensor in the plug as they are the screened ones
you can test the square wave signal with the ecu plugged in

 

Is creeded a typo?

 

just testing you

 

i spent approximatley 2.5 seconds trying to cure the abs fault on my 3 door before i thought fuck it and disconnected it lol, you dont need abs anyway

 

screeded, is that what they do to concrete floors?

 

I just like it to work matey.

 

Cheers matey.Thanks for all your help. So if there is a bit of dirt on the sensor or the pick up ring will i see this on my multi meter.

 

take the readings at 15mph of all four and post the results

 

Right i had a bit of a play with the abs. I must be doing something wrong or my multi meter is shit.

I could read the resistance from the pins on the abs loom but couldnt get the voltage.Ive got this bit of info ive been using.


This is my multi meter.Where does it need to be set at then cause i selected all of them and i all i can get to work is the resistance.

 

Osr wires are 6n24
Nsr wires are 4n22
Osf wires are 5n23
Nsf wires are 7n25

 

when did you last change the fluid?

also check the wiring to the cap as this can also cause issues

if the red light comes on it's a fluid warning light but most problems tend to be relay or sensor related