mmacneill123 0 Posted November 18, 2011 Hi peeps, found the comments on the buying guide handy here, had this prob when i bought the car a few months ago and all disks and pads have been changed since then as well as one of the rear calipers...so pretty confident brakes themselves okay, brake fluid okay as secondary clutch cylinder went and that all got replaced... Any ideas as to how to diagnose what is wrong? e.g. how do i clean the sensors, check they are working :-) Thanks Quote Share this post Link to post Share on other sites
VR6Pete 0 Posted November 18, 2011 I'd advise connecting your car on VAG-COM to see if any error codes are stored. Quote Share this post Link to post Share on other sites
mmacneill123 0 Posted November 18, 2011 Thanks for that, VAG-COM?? Is that the dealer diagnostic equipment at a dealer? :-) Quote Share this post Link to post Share on other sites
aide 0 Posted November 18, 2011 does it come on after you start to drive, or after a few minutes even when still? Quote Share this post Link to post Share on other sites
mmacneill123 0 Posted November 18, 2011 aide! I am pretty sure it is only after you start to drive, but will be cleaning it again tomorrow and will check... assume it stays off until you drive :-) Quote Share this post Link to post Share on other sites
aide 0 Posted November 18, 2011 the system is rather basic, general rule is if the light comes on and dissapears before moving, then the sensor check has been completed and all is okay, so assume its a mechanical issue, e.g. it senses the front wheels moving but not others. i'd check the gap between sensor and abs ring on the front, and also on the rears, unfortunately the rear check requires the calipers and disk to be removed. i just cleared an identical fault, it would appear at 15mph and above, it was an issue with the rear bearing seal interfering with the signal. Quote Share this post Link to post Share on other sites
budhilton 10 Posted November 18, 2011 Mine did this intermittently which I found strange so I had it checked on VAG Com which showed and ABS fault on the sensor that had just been replaced by the previous owner (F/N/S) So I had the error code cleared by VAG Com which fixed the problem. Don't ask me to explain why though :shrug: Andy Quote Share this post Link to post Share on other sites
mmacneill123 0 Posted November 19, 2011 Cheers guys, will visit VW shortly :-) Quote Share this post Link to post Share on other sites
Critical_Mass 10 Posted November 19, 2011 Definately sounds like a sensor. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted November 21, 2011 Could be anything, tbh.. sensors are the most common failure. Note that the ABS does a self-check when you reach 15 kph (about 10mph) on pulling away the first time after you start the engine. Until that point it doesn't know if all the valves work properly, so you might well have a faulty valve block if the light comes on just as the "crunch" happens there. They're cheap and reliable so buy a used one, don't even think about paying for a new one... Diags is the quickest way to find out what the problem is though, laboriously cleaning sensors is a last resort if you're a million miles from someone who has VAG-COM .. (or you don't own a laptop!). Quote Share this post Link to post Share on other sites
mmacneill123 0 Posted November 21, 2011 Diags is the quickest way to find out what the problem is though, laboriously cleaning sensors is a last resort if you're a million miles from someone who has VAG-COM .. (or you don't own a laptop!). So can i get hold of this VAG-COM? What do i need? I am totally green when it comes to Rado maintenance, are the front sensors on top of the struts? Do they just come apart? And taking the rear callipers off to get at the rear ones sounds challenging :-) Quote Share this post Link to post Share on other sites
dr_mat 0 Posted November 21, 2011 You can check the sensor resistances with a pocket multi-meter, and yes those cables on the suspension turrets go to the ABS sensors for the front wheels. Getting hold of a VAG-COM setup is pretty cheap if you already have a laptop running windows. Get any old USB VAG-COM lead off ebay (cheapest the better - the older designs tend to be more compatible with the old cars), then download the v3.1 (I think) version of VAG-COM from the Ross-Tech website. Run it, plug it in, hit the scan error codes button.. off you go. Quote Share this post Link to post Share on other sites
Roger Blassberg 0 Posted November 23, 2011 I have been having all sorts of strange goings on with the ABS on my '94 Passat. All sensors seem ok and the slotted rings on the hubs are new and clean. I decided to disconnect and clean the loom connector to the ABS ECU. That seems to have done the trick - these things operate at low voltages and any increased resistance, eg a dirty or corroded connection, can upset the ECU. It's worth a try in your case. Best wishes RB Quote Share this post Link to post Share on other sites
mmacneill123 0 Posted November 23, 2011 Any chance of pics to show me what is being talked about here as i am completely ignorant of what i should be looking at :-) ??? Quote Share this post Link to post Share on other sites
