ABS intermittent problems...

[guildmage 11]

Yes I know, this has been discussed in bazillion of threads but .. I couldn't find answer for my issue.

 

In short.

When I bough my car ABS light was ON all the time. Had a mechanic to look at it and after replacing Rear ABS sensor - my ABS was working fine, hooray :D It was simply working - was ON during ignition and then after few seconds it was OFF and stayed like that during driving.

After 2 weeks or so (after repair) I was waiting for my misses (was not driving but engine was running) and the ABS light came up... so I switched off the engine and started it up again - and the light stayed ON all the time :(

On next day, it was fixed again, ABS light worked as normal - no issues. For few days it was just fine, but then it just comes up and stays ON. There is no pattern to it.

 

Am I correct in thinking controller and pump is fine and I must have some electrical gremlin? I mean replacing sensor did fix the problem for like 2 weeks solid - after that, it's quite intermittent - and the light doesn't go OFF on some days, mainly it does so far.

Would it be beneficial to replace these 3 existing sensors - I bet these have never been replaced since the car was new? Or rather search somewhere else - if so any hints?

 

My MOT is in like 7-8 months so plenty of time - but I was so happy with the ABS fixed - that orange light on your dash is quite distracting :(

 

ps. I wonder if damp/water (as in rain) has anything to do with my issue?

I noticed slight damp on my passenger carpet today - but took carpet off and ABS controller was super dry, looked like new to be honest - and that little wet patch was maybe like 10cm2 not sure what the source yet - will research tomorrow in more details.

 

ps2. Last question (just crossed my mind) - I only checked the ABS controller from outside - I didn't disconnected it. Can I just disconnect it and then put it back as it was? Or there is any procedure I need to follow?

thanks guys

Edited October 28, 2011 by guildmage

[elliott 10]

Hello, just been through what your describing here.

 

The ABS system has more than a couple of common faults, might be best to check the plug that connects to the abs unit. Mine had some green corrosion around the contacts between the unit and the plug. Just give it a gentle clean with a small brush.

 

Also check the wire that goes from the top of the strut down to the wheel sensor on both sides of the front. My car has high millage and one of them had split inside the insulation. Pull the top and bottom connections off and check with a multimeter if you have one.

 

I did both of these and finally the light stayed out. If you have a laptop, a tool worth investing in is the VAG-COM cable. Its cheaper than replacing wheel sensors and saved me some guess work. It can't tell if the wire is faulty however :lol:

[VR6Pete 0]

Remove plug from abs ecu, even though it may look dry it more than probably ran down the loom straight into the plug / ecu... Had it with mine, and seen a few others on here with same issue... Have you tried getting it on vag com?

[guildmage 11]

Yes, it was checked with VAG com. This was indicated by faulty rear sensor by my mechanic. Like I said it did fix the problem for 2 weeks+ solid - was no issues whatsoever. That is why I was surprised that the issue re-appeared out of nowhere again. But then... it's intermittent so maybe I was just lucky for those first 2 weeks.

 

I will check today the connector on the controller and will see (so it is OK just to disconnect and then reconnect again the plug, I don't have to follow any reset procedure or anything, right?). Yeah, you can tell I'm uber noob ^^

 

Can always take it to mechanic again, but that means taking day-off and such ... so if there is any work I can do during weekends it's always a plus. Also I like to pick up the screwdriver and get personal with my car ... but I'm always so afraid of making things worse than they are. ehh need to grow up some manhood me thinks :)

[elliott 10]

Cant hurt to have a look, it'll save you time and money too. Disconnecting and reconnecting doesn't involve any procedures, just lift the metal clamp thing on the plug and the plug will lift out with it at an angle. Don't do what i did and pull the plastic cover off the top of the plug :lol:

 

Were all noobs at some point but you'll learn nothing if your not curious.

[guildmage 11]

Right, managed to check that ABS controller connector and it looks very clean, tidy and super dry. I cannot see how water could be anywhere near that controller, well check the pictures:

[ATTACH=CONFIG]49882[/ATTACH][ATTACH=CONFIG]49883[/ATTACH]

 

So next move is to organize another scan with vag com (may just invest into buying that cable then) and also check things with multimeter. I'm bit on a lost side with this, lack of tools and proper place - I live in flat so car on a designated parking place outside my flat :(

 

Also ABS light was ON today all time, even though yesterday it was working just fine.

[Mike Edwards 0]

If the problem clears itself if you switch everything off and then back on again, I would suspect the pedal position sensor. Easy to replace, but not cheap so it's worth getting the fault code read.

[Tuttle390 10]

Just about to buy a corrado, and the abs light is on constantly when driving, i have driven the car and breaks feel fine, the guy tells me it is the front left sensor that needs replacing .. Which will not be a problem if it is just that..

 

the guy seems genuine so this may not be an issue, however what would others think or do in this situation, also if it isnt this sensor could it be costly ?

[Mike Edwards 0]

The front sensor is the cheapest thing to replace. Offer to pay for its replacement as a condition of the sale.

[elliott 10]

Front sensor is £45 ish, take care removing the M6 cap screw. I snapped mine and ended up having to drill the old one out, not fun.