my abs light is staying on .......done all the checks i can and eveything is reading ok .......cant seem to find a fault....what is th 3 pin plug for that comes off the abs loom at the module?...is there any way of clearing this?

 

If its always on it most likely not a sensor. With a sensor fault the light only comes on after you exceeded 5mph IIRC

Stupid things like a fault level float and cause the problem you are having.

 

I had a faulty sensor on the back of my cossie.The abs light stayed on from start up.Check the condition.of the rear sensors on the suspension arms.They crack due to the alloy tube which the bolt goes through corroding.

 

First off check all four sensors resistance, they should all read 1Ω or higher!

Martin

 

Not true, an open circuit from a faulty sensor will cause just this problem, if the sender was a problem you will find the low fluid/handbrake warning light would also be illuminated!

Martin

 

have checked resistance of all wheel sensors and they perfect....low fluid warning lamp is not coming on ....pressure switch and pump working prefect .....just no abs when driving and abs light staying on ?????????

 

So they all are the resistance I stated or greater? If so then I would personally next look at cleaning the sensor, ABS rings, dirt can get in between the teeth.

Martin

 

sensors are reading 1.6 ohms ....car had bare shell rebuild so im sure the teeth dont have any dirt in them its sittin in my drive 2 years now with not much drivin done at all lol

 

You diden't inadvertantly spray get paint on the ring's did you?

Plus I had just realised I MEANT to say 1000 ohms resistance, I presume you don't meant you have 1.6 ohms?

Martin

 

can you trace wiring to abs ecu and check sensor resistance at the ecu terminals this will check the wiring running to each one, as if sensors ok at plug by the wheel might just have a wiring problem, think there is also a pressure switch on the master cylinder somewhere and the brake fluid level switch, dont think anything else influences the initial abs check, can be a bitch to find faults though. best of look.

 

car was sprayed as a shell so pretty sure no paint marty ......yeah meant 1600 ohms lol....cheked the sensor readings from the multi plug at the module so i know wiring is all good ....pressure switch works fine as pump comes on when gnition switched on then stops after few seconds ......its a brain teaser this one lol

 

I would be checking to see it you have risistance in the abs wires coming from the ecu.

Terminals 6and24 are the osr sensor.

Terminals 4and22 are the nsr sensor.

Terminals 5and23 are the osf sensor.

Terminals 7and25 are the nsf sensor.

 

first test is always the reservoir sensor This is a dual sensor cap unplug the white 2 wire connector and bridge it with a piece of wire ignition off.Once bridged switch the ignition on to position 2

 

yup that didnt sort it either
has to be a way of puttin a diagnostic on it surely ?

 

I would PM 'jon@work', he knows the system inside out, as the sensors are working and the level sensor is ok, you perhaps have a ECU or wiring problem?

Martin

 

I have some wiring diagrams if u need them.

 

cheers lads i have a workshop manual and all wiring seems perfect so im thinkin it the abs module at this stage

 

Let us know how you get on then fella.

 

Nope, Teves Mark 2 has no diagnostic output.

If it's 2wd, you have 3 relays to check - the orange one in position VII in the fusebox which is an inhibitor to stop the hydraulic pump running while the engine's being started (4x4s have this integrated in the ECU), there's a green one behind the glovebox which powers the system, and there's a purple one behind it which runs the hydraulic pump. The latter two relays are fused - the hydraulic pump etc can run independantly of the rest of the system, so if the fuse for the green relay's popped (cutting the system off), you'll still have power assistance for the brakes.

As already mentioned, a running wheel sensor fault can only be detected above 5mph. A disconnected wheel sensor is detected immediately - check they're actually connected on the chassis rails for the front, and under the rear bench, and not worked loose. The resistance for the wheel sensors isn't as important as the AC voltage that comes out of them. Resistance only tells you a sensor's connected, the AC voltage tells you the signal's strong enough for the ECU to use as a reference.

Leave the two pin connector on the reservoir bridged while you're diagnosing it - this will rule out the switch in the float column.

Only things you really have after that are the solenoids in the valve block (check this has the relevant earths and multiplug attached), and the pressure switch in the hydraulic unit, which are unlikely to have failed if they've not been meddled with.

 

ok so i have no eletrical problem
fuses and relays are all working
pump knocks on and off as it should
and all sensors are reading correctly
all earths are good .........
light still on .....
?????????????