winton05

Can anyone give me some ideas on my abs system and the issues I am having with it?.
When I turn the key on, the orange abs light comes on. When the car starts it goes off after a few seconds, but once i start moving it will come back on again and remain that way. The brake pedal also feels quite hard with not a lot of feeling to it, but the abs pump is pumping up? I have checked the front sensors and apart from a clear type grease in there the sensors are clean. Where do I start.

Mike Kerbey

iTrader: (1)

Have a look at the back sensors aswell. You can also check the resistance of each sensor to make sure they are ok. I cant remember the figure that they should be off the top of my head though! Im sure someone else will remember...

JamesH

iTrader: (21)

Pretty sure it'll just be a relay under the passenger side dash. 2x pink and one green from memory

JamesH

iTrader: (21)

Pretty sure it'll just be a relay under the passenger side dash. 2x pink and one green from memory

winton05

okay, know the three relays you are talking about, can anyone tell me what the two pink ones are for and what is the green one for?

JamesH

iTrader: (21)

Just take them all out and test them mate

hillzy2k

if im right the 2 pink ones are identical and both control the pump. the abs, although tied in with the master is actually seperate. you can unplug the ecu and valve block and your electro-hydraulic master should still operate fine. if it doesnt and still goes hard, the fault may be either the pump, 2 pink relays, or the pressure switch at the master cylinder. if however the pedal and pump assembly work fine with ecu/valve block disconnected, the fault could well be one of the sensors due to dirt ingress, corrosion of wiring, or just a faulty sensor. il try to find the resistances for the sensors for you.

tabetha

Have a look on the rear abs rings for rust build up, I had this and it was that that was causing it, a sit missed a few gaps as rust was bridging the gaps, didn't do it all the time, confused me but was defo that, has been fine since sorting these.
tabetha

winton05

Okay, I cleaned up the rear sensor rings from what I could, is there an easy way to do this ( to get right in there or does the assembly have to come apart ). I have found the pedal feels more precise. But the orange abs light still comes on when I drive off as soon as I hit 10 mph?? The brakes do now seem to be working as they should, it just this light!

Turbo Zetec

iTrader: (1)

start by removing the abs unit, then proceed to throw it in the bin. after that, the newly aqquired space will allow you to fit a nice 'regular' master cylinder and servo

worked well on mine

The Crocodile Hunter

I have had the same or very similar problem with mine for ages

It was all working fine untill i broke one of the front sensors taking it out.

Got hold of another sensor and the light went out untill you started driving then comes on. Tried another sensor and still the same, although the brakes feel fine on mine??

Just never got around to fixing it, i wonder if it is one of the relays mentioned above??

winton05

Hi, no just been through all the relays associated with the abs and they are all operating as normal. the pump is working as it should, the sensor rings are clean, the fuses and relays are good. All there is to check can be the ohms levels on the sensors. It sat for 6 months and this problem just arose gradually after this time. the brakes seem fine but I still feel a little uneasy with the hard brake pedal. No one in New Zealand seems to have any ideas as I guess there just are not that many still on the road here.

The Crocodile Hunter

I do wonder if my pedal does feel hard and i've just got used to it? Although when the abs light first came on i dont remember it feeling different?

When i had the MOT done this year the tester thought so but the brakes passed fine?

When you first start yours from cold do you get the fluid level warning light staying on for a few seconds then going out?

Does anyone else have this? Think i remember someone before saying that the system is just doing a 'system check'?

winton05

Both the orange abs light and handbrake light should come on with the ignition and on start up. After 5 seconds the self check should send these lights out if all is okay.
My abs light will only come on once my car hits 10 mph and then stays on, but the brakes work fine ( I think ) although the pedal feel is quite hard, but is this normal for this set up?

The Crocodile Hunter

mine is the same, although the handbrake light stays on a little longer and you can hear a buzz from the abs pump while its on, sure this is normal though??

My orange abs light only comes back on on when you start moving too

Sure the hard pedal is quite normal too, other people who own cossies have driven my car and never said anything about it??

I've just always thought my problem was due to the sensor i broke and/or i damaged the sensor ring. To be honest its never really bothered me but i'd still like to get it sorted if anyone knows what it is????

winton05

your problem sounds just the same as mine, I am going to do an ohm test today on my sensors and will let you know

iansoutham

If your sensors all test okay (ohms should be around 900-1100ohms) and the ABS sensor rings are fine, then try checking the wheel bearings.

Sounds silly, I know, but I had this problem on my 4be, but the light would come on randomly and then stay on until the ignition was turned off.

The car passed an MOT fine, all sensors were checked and exchanged for other known good ones and still the problem persisted. Decided to check the wheel bearings, just in case, and both passenger side ones had about 1/4 turn before going solid. This was using a 3/4" breaker bar and standing on them. The bearings go to something like 330lb ft on the front and about 250lb ft on the rear. Mine were still tight enough to hold the bearing, but when under load, allowed the ABS sensor ring to move just enough to put the air gap out of spec with the ABS sensor.

Might not be the problem, but might be worth checking before you go looking for something that might not be there.

PeterRST

iTrader: (1)

Measuring resistance will only tell you if the wire to the sensor is broken.

What you really want to measure in order to find out whether it's a wheel speed sensor related problem is voltage.

You can do this directly at the multiplug that goes into the ABS control unit behind the glove box. Get yourself a wiring diagram and find out which pins are for which sensor (or take a photo of the plug and I might be able to help you out). Let someone else drive the car while you measure the voltages (AC!) created.

They should be equal on all 4 wheels (except when the car is turning). The values will proportionally increase with speed. On my 4x4 I measured 0.1 - 0.2 Volt when the car was just rolling and about 0.5 - 0.7 Volt at 25 mph.