Weird ABS issue

[Spirit]

Had the following fault for a few weeks:

At a slow speed (10-15mph) and usually turning slightly left, the ABS would kick in. It appreared one of the ABS rings on the front had bust (similar to a similar issue I had last year), so managed to aquire a replacement CV joint.

Funny thing was though, the ABS sensors where reading correctly, unlike before when the broken one showed a dramatic difference in wheel speed.

So, CV joint replaced.......and same fault still there.....anyone got any ideas ?

The car/braking is fine with the ABS fuse pulled and at higher speeds......./Grrr

[stuartturbo]

have you fault tested it
It could be the ecu is shot on the abs unit

[Spirit]

have you fault tested it
It could be the ecu is shot on the abs unit

Yep, no joy with that.

Current thinking is either faulty ABS ECU, or a wiring fault somewhere

[stuartturbo]

I'll ask at work to see if we can check them
swap with a good one should unbolt with out removing abs motor( no bleeding required)

[BraindG]

is it deffo abs kicking in?

I had problems with mine when i done my work, pressing the brake would create a noise very similair to abs kicking in.. but it wasnt...

have you done any work on front of car?

[bradc]

obviously checked the other side's abs ring?

As Barry asked though, it could be something else, like the pads binding onto the disc, or skipping on the disc, or something else silly like that.

[Gowf]

I'm sorry to hear that the CV joint didnt sort the problem. I see what you are saying though... if it works fine with the fuse removed it must be abs related.

have you had the sensors disconnected at all prior to it starting?

[Nick Mann]

Where is the ABS ECU? Is it something we could swap about at JF?

[stuartturbo]

should be on the abs unit itself looks like part of it
New job does this type of stuff will have a look in the light of day an try to work out what type it is some unit you can split

[Spirit]

It's defo an ABS issue, the pedal pulses as it does with ABS kicking in.

As stated, with the ABS fuse pulled everything is perfect.....no binding etc....and no work has been done on the front of the car recently.

[Spirit]

Has anyone ever changed an ABS solenoid ? Got a feeling it may be a short on the front right ABS solenoid.

[BraindG]

theres and article about it removing the solenoid.

One thing i learnt from my work i done, - stick a volt meter on it, and 20 ohms (wouter?) and it should read in the region of 1380 ->1410.

[Wouter]

I think it was 200 Ohms or may be 2k, it should give a reading regardless.

[Spirit]

Everything checked out by AP, all wiring etc tested and no faults found anywhere.

The only thing Kev could now suggest was to try another ABS modulator, so have left it with Mo to see if he has one.

Getting a bit p*ssed off with this now /Grrr

[stuartturbo]

Forgot to check at work today about that

[Spirit]

Now worries thanks anyway mate.....will wait to see what Mo turns up.

[White Lightning]

Bugger ... /Grrr

[Slimshady]

Hi Pete, did you ever find a solution to this problem, I have a very similar thing happening with my car.

At low speed I put my foot on the pedal and BUMP BUMP BUMP BUMP….. kick back as though the ABS has kicked in but the car still brakes. The ABS light dose not come on.

At first I suspected the pads so I pulled it all to bits and I have about ¼ pad life left + disks look ok.

I have not removed the fuse but I will try this soon (is this in the main box or the small box near the windscreen, looks like a relay)

Was this a sensor fault or something else, come to think of it where is the sensor?

Thanks in advance


Ninja Neil
AKA Slim

[Spirit]

Turned out to be the ABS modulator on mine...luckily I got one from Mo second hand.....damn they're expensive ! Get a MUT-II on it if you can and get the sensors checked out.....you may have a split abs ring

[Slimshady]

Thanks Pete, I actually went to Mitsy in Norwich this morning and the chap said “its your disks m8” he didn’t even look at the car – he’s either a prat or he has seen this before many times and is actually intelligent. You decide!!

When I get a chance I will take them off and measure the run out on the lathe at work if I have plenty of meat left it might be worth licking a few thou’s off.

[Spirit]

First thing I would do is pull the ABS fuse. If you still get the pulsing through the pedal then it may be disks, but there's no way the guy would no without driving it. The feel from the ABS is different to warped discs IMO anyway.

Will just go off and confirm the fuse to pull for you.

Edit: Fuse is no.16 in the engine bay fusebox on the VR4 http://www.clubvr4.com/forum/uploaded/3/1173775253.jpg - just check the lid for yours in case it's different.

[Slimshady]

Thanks for the help Pete (very very good advice) I pulled No 16 out and just as I suspected the fault disappeared. A few days later I jacked the car up and inspected the FOS ring – yes my ring is split, and rusty (pardon the pun) a couple of mm in one of the groves – bugger – but at least with your help I think I have solved the problem and saved a couple of quid i.e. could have booked the car in to have the disks and pads replaced only to find I still have the same problem.

Thanks again

Neil

[Spirit]

Glad to be of service Neil, and good luck sorting it out. All four rings have now been replaced on mine so hopefully it's the end of my abs issues for a while.