Abs Problem

[linkgreen]

Hi

 

This morning my wife returned from dropping our daughter at work, and asked "what does the ABS light mean?"

 

"MONEY" I replied.

 

Sure enough the abs lamb is permanently on. As soon as the ignition is switched on the lamp comes on and fails to extinguish. Previously it went out after 2-3 seconds, but now it just stays there.

 

I know its a safety thing and an mot failure so I am obviously keen to sort it.

 

The brakes have felt a little spongey recently - could it be the fluid ? or is it more likely one of the wheel sensors?

 

I've not had any problems previously with abs and know very little about it.

 

I assume there is a control box and pump as well?????

 

Any ideas

 

Thanks

 

Linkg

[Guest Paul Collins]

I'm having the same problem at the moment.

 

I'm looking into (hoping) a dodgy sensor, but the weather here is horrible, so it can wait until tomorrow.

 

From what I think happens, the abs control unit does a self test when you switch the ignition, shutting the light off when everything is ok.

 

I did have a couple of problems a while back where the light went out, but then came on when I got moving. When it did this, I reached into the O/S wheel arche and unplugged the sensor wire, then plugged it back in.

 

This time, my usual fix doesn't work, so I'm assuming (hoping again) that it's a wiring fault.

 

If you have access to someone with diagnostic equipment, apparently that can tell you which sensor. Then tell me who did it for you.

 

Whichever one of us fixes it first, shout :D

[linkgreen]

Thanks for the reply.

 

Unfortunately I don't have a friend with the diagnostics, but I'll certainly look at the sensors/wiring first.

 

I recently changed the oil, so I may have disturbed something in the wheel area taking the sump guard off, but it's been over a week since I did that, and the fault only appeared today.

 

The weather here is also bad, so I will be lucky to look at it tomorrow.

 

Have you changed your brake fluid recently? Could this be an issue?

 

If I find anything I'll let you know.

 

Thanks

 

linkgreen

[Guest Paul Collins]

Ihaven't touched my brake fluid (apart from checking the level). I would have thought the fluid level switch would trigger the brake warning light, not the ABS light.

 

I suppose this sort of weather is more likely to crud up the sensor ring on the hub, so checking there could help.

 

Paul

[linkgreen]

Hi Paul

 

Whats all this about sensor rings and hubs?

 

Is it obvious once I get my head in there and have a good look?

 

Are you saying it could be a case of just cleaning some crud off?

 

Paul G

[johnb80]

If it was a fault with the sensor ring the light would extinguish initially then come on when you set off. If the light is staying on from startup the system is failing the static tests i.e. Sensors, Modulator or the control module.

 

Regards - John

[Topbloke]

stupid question i know but are the brake lights working ? ? :D

[Ivor_E_Tower]

...check the switches on the brake pedal arm under the dash too.

[Guest Paul Collins]

Went out this morning, got to 10-15mph and the light went out. All I can assume is that it was a sensor wire problem and the system reset itelf at a preset speed.

 

No I'm going to worry about it coming on during the test :D

[johnb80]

10 - 15 mph is when the system looks at the wheel sensors to see if it's receiving a signal from them.

 

Regards - JB

[Guest Paul Collins]

10 - 15 mph is when the system looks at the wheel sensors to see if it's receiving a signal from them.

 

Regards - JB

Thanks John

 

Whe I fiddled with the connectors yesterday, I didn't take it for a drive, just turned the ignition on.

 

So what's the 3mph mentioned in the TIS then?

 

Paul

[johnb80]

Maybe it is 3mph, it's slow anyway, you can usually hear the abs do its stuff just as you set off the first time. Sounds like you had a dodgy connector and now the system has seen all of the correct signals it's a happy little bunny.

 

Well done that man.

 

Regards - JB

[linkgreen]

Hi again

 

I've checked the sensor wiring- unplugged cleaned and reconnected, abs light is still on!

 

Checked the brake lights are satis- they are! abs light still on!

 

Checked the relevant fuses( 9,10 & 28) - all satis, abs light still on!

 

Previous posts talk of modulator, control box and brake pedal switches.

Can someone tell me where these are and what, if anything I can do to check them!!

 

PS

Whilst I was in the fuse box I had another look for fuse 35 for the cigarette lighter and I still can't find it- last time I took the complete fuse box out and split it and still couldn't see it- I'm not doing very well at the moment!!!!!!

 

Thanks in advance

[Guest pnwheels]

If its the rear cigarette lighter sockets, these fuses are under driver's seat

[linkgreen]

Hi

 

I've checked the 2 fuses under the drivers seat previously - and they are fine!!

 

Thanks anyway

[Masked Marauder]

Hi again

 

PS

Whilst I was in the fuse box I had another look for fuse 35 for the cigarette lighter and I still can't find it- last time I took the complete fuse box out and split it and still couldn't see it- I'm not doing very well at the moment!!!!!!

 

Thanks in advance

Who told you the cigarette lighter was fuse 35? It should be fuse 7.

 

If your car is pre 05/99 it should be 20A, post 05/99 25A

[Velcrohead]

Hi

 

I've checked the 2 fuses under the drivers seat previously - and they are fine!!

 

Thanks anyway

Where in the country are you linkgreen?.

If you are close to me, Royston Hertfordshire, Then I have VAG COM to see what the modules say.

[linkgreen]

hello again

 

MM

I got F35 from previous posts here- I'm now going to check F7 as soon as my wife returns in the Gal.

 

Velcrohead

I'm in the NW - just outside Chester- perhaps a bit far but thanks anyway!!

 

link

[Masked Marauder]

F35 was upto 1997

[linkgreen]

Hi again

 

Thanks MM

Just checked F7 -blown- replaced it- cigette lighter now works- wife can charge phone again!!!!!!!!

I bow to your superior knowledge.

 

What are you like on abs?????

 

Thanks

A Humble linkgreen

[Velcrohead]

Velcrohead

I'm in the NW - just outside Chester- perhaps a bit far but thanks anyway!!

 

No worries linkgreen.

Yes probably a bit far.

[Masked Marauder]

 

What are you like on abs?????

 

There is no shortcuts, you have to run the diagnostic program, either at the dealers or using VAG-COM

 

I will be getting VAG-COM in the near future, I have a couple of jobs that need doing. The price the dealers charge, I would advise anyone else to do the same, it would not be long before it has paid for it's self.

[Guest Paul Collins]

Has anyone looked into thes handheld code readers that small workshops use?

 

They are a lot cheaper, and if they read the codes, they read the codes, or am I being simplistic :blink:

[linkgreen]

Hi again

 

Finally got round to checking the wheel sensors. 3 of them con check at around 1Kohm, but the rear drivers side shows open circuit. It looks pretty easy to change

 

Does anybody know the best place to pick one up and at what kind of price?

Is the scappies an option?

 

Assuming this does clear the fault - do I need to reset the fault codes/abs system somehow?

 

Thanks

linkgreen

[Guest Paul Collins]

http://www.gsfcarparts.com/

 

I'm not sure if you would need to get the fault code reset. Mine just reset itself when I got moving.

 

Paul